The next time you pull out that American Express rewards card to pay for a $2 hot dog, reconsider. That cozy, family-owned restaurant is losing 50¢—or a quarter of the price tag—to the banks when you do. each swipe of a credit card costs 20¢–50¢, plus one to five percent of the check, depending on the type of card. That adds up, especially when you consider that in 2008, 68 percent of restaurant payments were made with credit or debit cards, according to Hitachi Consulting.

Judd Murphy, co-owner of Birchwood Kitchen, says credit-card processing costs about $10,000 a year, or 2.5 percent of revenue. he doesn’t necessarily mind when customers use a card for just a cup of coffee, but there are definitely little things customers can do to help. For instance, stop splitting a dinner bill over four cards—that’s four transaction fees rather than one. And if you have to pay with a card, consult the chart below first, where we’ve organized your options from friendly (at top) to downright cruel.

CASH
Nothing beats cash. Businesses don’t pay processing fees to receive the money, and unlike every other payment method you have, cash also provides small businesses with immediate revenue. Banks can take as many as three business days to process cards or checks, and it’s tough to order supplies without a lot of capital.

CHECKS
Businesses receive the full bill when paid with checks, but there are drawbacks, too. They have to be deposited to the bank, which can be a pain when so few people use checks. Quick-serve restaurants also don’t like them because they take time to fill out, which holds up service. And like cards, it takes a few days for banks to actually give that mom-and-pop the money it has coming.

DEBIT
If given the choice to sign or punch in your PIN, always go with the latter. It’s the cheapest way to process a card and also the most secure. if you have to sign for it, still know that paying debit is better than credit.

VISA AND MASTERCARD
MasterCards cost slightly less to process than Visas, but they’re about even. if you have to use one of these cards, avoid rewards cards. A one-percent cash rewards card might sound like a sweet deal, but who’s paying for that reward? It’s not the credit-card company or the bank. It’s the bakery down the street. Rewards cards cost businesses an extra 0.75 percent on average, according to the Federal Reserve.

VISA AND MASTERCARD BUSINESS
If you have a business version of Visa or MasterCard, know that it’s doing the business you’re eating at no good. They cost significantly more to process than a regular Visa or MasterCard and a little more than rewards cards.

DISCOVER OR AMERICAN EXPRESS
American Express generally charges businesses the most when it comes to fees, with Discover just behind. In a second blow, businesses negotiate with these corporations individually on rates, which means that small businesses with very little leverage tend to pay a lot more than the big guys.

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