THE GUIDE · THE CARD MACHINE

One tap. Four kinds of money.

Debit, credit, charge, prepaid - and the commercial cards underneath B2B. They look identical at the terminal, but the money underneath comes from four different places, at four different times, and at four very different prices.

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IN PLAIN WORDS — READ THIS FIRST

Five cards, one tap. At the terminal they are identical plastic. Underneath, the money comes from five different places: your own balance (debit), the bank's money you repay later (credit), money you must clear in full each month (charge), money you loaded up front (prepaid), or a company's money with paperwork attached (commercial).

Why care? The card type sets the price the shop pays, and it decides whether the payment even goes through. A rewards credit card can cost a merchant roughly seven times what a regulated debit card costs on the same $100 sale. First the machine, then the quiet ways each card type fails.

PART 01

Where the money actually comes from.

Same tap, four funding stories. Step through debit, credit, charge and prepaid and watch which account moves - and when.

PART 02

The four families.

What each card really is, who profits from it, and why your rewards card is the expensive one.

DEBIT · YOUR MONEY

"Spend what is already yours."

A debit card draws straight on your bank balance. In the US its interchange is capped by the Durbin Amendment for big banks - which is why merchants love it and its rewards are thin. Small banks (under $10B) are exempt and earn several times more. Elsewhere, debit is simply the default account-linked card.

CREDIT · BORROWED

"A loan at the point of sale."

Credit cards let you spend the issuer's money and repay later. The issuer earns three ways: interchange on every swipe, interest when you revolve, and fees. Rewards are funded largely by that interchange - which is why credit costs merchants the most.

CHARGE · PAY IN FULL

"Access, not a loan."

A charge card must be paid in full each cycle - no minimum payment, no revolving interest. Classic American Express and corporate travel-and-entertainment cards are charge products; the value is spending power and float, and the revenue is fees and interchange, not interest.

PREPAID · LOADED FIRST

"A wallet with a card number."

Prepaid is a stored balance: load it, then spend it. It powers payroll, gift, travel and benefit cards - and it brings the unbanked onto card rails. It is not a bank account, so deposit-insurance protection depends entirely on how the funds are held (see Field Notes).

COMMERCIAL · BUSINESS

"Cards that carry paperwork."

Purchasing, corporate T&E and fleet cards move business money. They carry higher base interchange but can qualify for lower Level 2/3 rates when the merchant passes line-item data (tax, PO number, item detail) - the B2B optimisation that AP teams live on.

CO-BRAND vs PRIVATE-LABEL

"Whose logo is on it?"

A co-brand card (airline, hotel, retailer) runs on a network and splits rewards and interchange with the brand. A private-label store card is issuer-run and often accepted only at that retailer - the vehicle for deferred-interest promos and a surprisingly large lending business.

The words, one at a time.

Six terms decide what a card costs and whether it works. Learn these and the price tables stop being a mystery.

Interchange
the swipe fee, set by the network
The fee the merchant's bank pays the card's issuing bank on every sale. It is the biggest slice of what a card costs a shop.
A $100 consumer-credit sale carries roughly $1.80 of interchange. The same sale on regulated debit carries about $0.22.
Why it matters: interchange is why card types have different prices, and where your "free" points are funded.
Durbin cap
the US law limiting big-bank debit fees
The Durbin Amendment caps debit interchange for banks over $10B in assets. Smaller banks are exempt and earn about double.
The cap is 21¢ + 0.05% + 1¢. On a $100 debit sale at a large bank, that's about 22 cents.
Why it matters: it's why debit is the cheap card in the US, and why merchants steer you toward it.
Level 2 / Level 3 data
extra detail that lowers the rate
Tax, purchase-order and line-item detail a merchant sends with a commercial-card sale to qualify for cheaper interchange.
Passing full Level 3 data can cut 50–100 basis points off a corporate-card sale (0.50–1.00%).
Why it matters: it's the single biggest lever in business-to-business card acceptance.
Pre-authorization hold
money frozen before it's charged
A temporary hold that reserves funds against your available balance before the final amount is known and charged.
A gas pump holds $100, then charges $40. The other $60 stays frozen for days before it unlocks.
Why it matters: holds are why debit and prepaid cards fail at hotels, pumps and rental counters.
Float
the free days between spend and pay
The stretch where the issuer has fronted the money and you have not repaid yet. No interest if you clear in full.
Buy on day 1, the statement clears on day 25: up to 24 interest-free days of the bank's money.
Why it matters: float is the product a charge card sells. Debit and prepaid give you none.
Revolving
carrying a balance and paying interest
Repaying less than the full statement, so the rest rolls into next month and accrues interest.
Carry $1,000 at 24% APR and you pay roughly $20 a month in interest until it's cleared.
Why it matters: revolving interest, not interchange, is the biggest profit line on consumer credit.
PART 03

What each card costs the merchant.

The card type sets the price. Here is roughly what the same $100 sale costs, by what the customer taps.

Regulated debit big-bank, Durbin-capped
~0.3%
Exempt debit small-bank, uncapped
~0.8%
Consumer credit plain vanilla
~1.8%
Rewards / premium credit the points come from here
~2.3%
Commercial card corporate / purchasing
~2.7%
Illustrative US effective interchange on a typical ticket - exact rates depend on the network table, ticket size, MCC and card program. Regulated debit reflects the Durbin cap, itself in legal flux (see Field Notes).
PART 04

The tell is in the number.

Before you even tap, the first digits announce exactly what kind of card this is.

// ANATOMY OF A CARD NUMBER — 4242 4242 4242 4242

4  —  MII: major industry (4 = Visa, banking / financial)
4242 42  —  BIN / IIN: network + issuer + country + product
424 2424 24  —  the issuer's own account range
2  —  check digit: the 1954 Luhn formula, catches typos

// The BIN is the card's DNA. Before you tap, it tells the terminal: debit or credit, consumer or commercial, which country, which rate table. Pull one apart in the Card Anatomy and BIN tools.
WHEN IT BREAKS

When the wrong card says no.

Same tap, five kinds of money — and five ways it goes wrong. Three failures that surprise people, then a tree for the moment a card gets declined at the counter.

FAILURE 01 · THE HOLD
Declined at the hotel, fine everywhere else
WHAT YOU SEEYour debit or prepaid card works at the shop but gets refused at a hotel, gas pump or rental counter.
WHYThose merchants place a pre-authorization hold — sometimes far above the final bill — that freezes part of your balance. The card has money; it doesn't have available money. Prepaid cards also often block recurring charges by design.
THE FIXUse a credit or charge card where holds are common. On debit, expect the frozen amount to release over several days after checkout.
FAILURE 02 · THE DOWNGRADE
The "qualified rate" that never applies
WHAT YOU SEEA merchant was quoted a low headline rate, then gets billed far more on the statement.
WHYThe cheap rate only fits regulated debit. A rewards or commercial card lands in a pricier bucket, and a commercial card that doesn't transmit Level 2/3 data pays top interchange. The card mix, not the quote, sets the real cost.
THE FIXRead the effective rate, not the teaser. Enable Level 2/3 for business cards, and expect a rewards-heavy customer base to cost more.
FAILURE 03 · THE FROZEN BALANCE
The gift-card money that locked up
WHAT YOU SEEA prepaid or gift program pauses and the balance you loaded is suddenly unreachable.
WHYPrepaid is a stored balance, not a bank deposit. Deposit insurance only passes through if the pooled account is titled correctly. When the program manager or its bank fails, that titling decides who gets paid — the same reconciliation risk the money chapter warns about.
THE FIXTreat large prepaid balances as an IOU, not savings. Check who holds the funds and whether pass-through insurance actually applies.
THE CARD WAS DECLINED. WHICH KIND OF DECLINE?
1 · Is it a debit or prepaid card?
YES — CHECK AVAILABLE BALANCEA pre-authorization hold or a pending charge may have frozen funds. Prepaid can also block recurring payments and holds by design. The money can be there without being spendable.
NO — KEEP GOINGCredit or charge card? Go to step 2.
2 · Is it a credit or charge card?
OVER LIMIT / UNPAIDCredit declines when you're over the limit; a charge card blocks new spend if the prior statement isn't cleared. The issuer's fraud model can also freeze an unusual pattern.
LIMIT IS FINE — KEEP GOINGGo to step 3.
3 · Is it the right card type for this merchant?
TYPE / NETWORK NOT ACCEPTEDSome merchants don't take certain networks or commercial cards; cross-border and category blocks are common. The terminal read the BIN and said no before anything else.
EVERYTHING CHECKS OUTThen it's likely an issuer risk decline. The customer calls their bank, not the merchant. The decline-code tool translates the exact reason.
COMMON QUESTIONS — ASKED PLAINLY

The things everyone wonders.

Five questions people actually ask about the card in their pocket.

WHY DID MY DEBIT CARD GET DECLINED AT A HOTEL BUT WORK EVERYWHERE ELSE?
A pre-authorization hold. Hotels, gas stations and rental firms don't know the final amount up front, so they freeze an estimate — often well above the real bill — against your available balance. On a credit card you rarely notice, because you're borrowing the issuer's money. On debit or prepaid the hold eats your own cash, and if the balance is tight the next purchase bounces. The frozen amount usually releases a few days after you check out, once the final charge lands.
WHO ACTUALLY PAYS FOR MY CREDIT-CARD POINTS?
Mostly the merchant, and quietly, you. Every time you tap a rewards card, the shop's bank pays interchange to your issuer, and a chunk of that funds your points. Merchants recover it by charging everyone slightly more, so cash and debit users partly subsidise card rewards. The issuer also earns from you directly through interest if you revolve and through annual fees. The receipt never shows any of this, which is exactly why it works.
IS A PREPAID CARD AS SAFE AS MONEY IN A BANK ACCOUNT?
Not automatically. A prepaid balance is a stored value the program holds for you, not a deposit in your name. Whether it's protected if the company fails depends on how the pooled account is set up — "pass-through" deposit insurance only works when the records clearly show who owns each slice. For small everyday amounts this rarely bites. For a large balance, it's worth knowing who holds the money and whether the protection actually reaches you.
WHAT'S THE REAL DIFFERENCE BETWEEN A CHARGE CARD AND A CREDIT CARD?
A credit card lets you carry a balance and pay interest on it. A charge card makes you clear the full statement every cycle — no minimum payment, no revolving interest. What a charge card sells is float and spending power, not a loan. Classic American Express and corporate travel cards work this way. Miss the full payment and the penalty is steep, because the product was never designed for you to borrow.
CAN A MERCHANT CHARGE ME MORE FOR PAYING BY CREDIT CARD?
Sometimes, depending on where you are. Card networks used to ban surcharging outright; many places now allow a capped surcharge or a cash discount, while some countries and US states still restrict it. In the EU, surcharging on most consumer cards is banned because interchange there is already capped low. When you see "3% fee for credit," the merchant is passing back the cost this whole chapter is about — the card type's price.
FIELD NOTES — THE PRO LAYER

For the professionals.

The families up close - the debit cap that landed in court, commercial data, prepaid's many species, and the virtual cards eating B2B.

DURBIN — THE DEBIT CAP THAT'S NOW IN COURT
US debit interchange for banks over $10B in assets is capped by the Fed's Regulation II at 21 cents + 0.05% + a 1-cent fraud adjustment; smaller issuers are exempt and average roughly double. The Fed proposed cutting the cap to 14.4 cents + 0.04% in Oct 2023 - and then in Aug 2025 a district court vacated the standard entirely, ruling the Fed had baked in costs the statute doesn't allow. The ruling is stayed pending the Fed's Eighth Circuit appeal, so the 21¢ standard still applies in practice as of Jul 2026, and a Kentucky court reached the opposite conclusion — the number is contested, not yet changed. Durbin also forces two unaffiliated debit networks per card, enabling merchant least-cost routing - a bigger deal than the cap for many acquirers.
LEVEL 2 & LEVEL 3 — WHY COMMERCIAL CARDS CAN COST LESS
Commercial cards start at higher interchange, but qualify for cheaper Level 2 (tax amount, customer code) and Level 3 (full line-item detail - quantity, unit price, product code) rates when the merchant transmits that data. For B2B and public-sector sellers, passing L2/L3 can cut effective rates by 50-100 bps. It's the single biggest lever in commercial-card acceptance - and why B2B gateways advertise 'Level 3 enablement.'
PREPAID'S MANY SPECIES
One rail, many products: GPR (general-purpose reloadable), payroll, gift (open-loop network vs closed-loop store), EBT (government benefits), travel/FX and incentive cards. In the US they fall under Reg E and the CFPB's prepaid rule. The subtle risk: prepaid balances aren't automatically insured - pass-through FDIC insurance depends on how the program titles the pooled account. A prepaid balance can be an IOU on an IOU - exactly the reconciliation risk the money chapter warns about.
VIRTUAL & SINGLE-USE CARDS
A virtual card is just a card number minted on demand - often single-use, locked to one amount and merchant, and auto-expiring. Consumers use them to fence off subscriptions; the explosive use is B2B accounts payable, where one virtual card per invoice replaces checks, earns rebates and reconciles itself. Virtual commercial-card spend is growing fast because the card is the control. It leans on the same tokenization and issuing machinery covered in those chapters.
CO-BRAND ECONOMICS — THE RETAIL PARTNERSHIP
A co-brand card (Delta, Amazon, a hotel chain) is a negotiated business: the brand brings customers and takes a share of interchange and rewards funding; the issuing bank brings the balance sheet and lending. Private-label store cards go further - issuer-run, sometimes accepted only in-store, and built around deferred-interest promotions that are lucrative and heavily scrutinised. Both turn a loyalty relationship into a lending book.
PART 05

Remember three things.

1
The tap looks identical; the money underneath is not. Debit spends your balance, credit spends the issuer's, charge is float you must clear, prepaid is a stored balance you loaded first.
2
The card type sets the price. Regulated debit is cheap by law; rewards credit and commercial cards are the expensive end - which is why the 'free' points are quietly funded by interchange you never see on the receipt.
3
The BIN tells the whole story before you tap - network, issuer, country, debit-vs-credit, consumer-vs-commercial, and which rate table applies. It is the first thing every terminal, gateway and fraud model reads.