They’re a gas-station staple beside the beef jerky and taped officiously to the cash register — the handwritten signs announcing a $5 or $10 minimum purchase for credit card transactions.
They’re also against the rules.
Visa and MasterCard merchant agreements prohibit businesses from setting minimum or maximum purchase limits, adding a surcharge to credit card purchases or requiring cardholders to show photo ID.
“Always honor valid Visa cards in your acceptance category regardless of the dollar amount of the purchase,” states the Visa Card Acceptance and Chargeback Management Guidelines book. “Imposing minimum or maximum purchase amounts in order to accept a Visa card transaction is a violation of the Visa rules.”
Businesses post and enforce the minimum purchase policies with little resistance because few customers are aware of the terms of their contract with the credit card companies. Fewer happen to have the manuals folded in their back pockets when confronted with such a restriction.
Fortunately, a blog is turning the tables on credit card agreement scofflaws. NonToxicReviews has designed clippable, wallet-sized cards bearing the relevant rules. You can hand them to those recalcitrant cashiers and mealy-mouthed managers who don’t want to charge a single soft drink to your Visa debit card.
Click here to print the cutout cards
Stores set minimum purchase limits because credit card companies charge them a transaction fee every time you pay with plastic money. On inexpensive items, these fees shrink the already miniscule profit margins they make on the sale. The rules are clear, however; merchants must absorb these fees and chalk them up to the cost of doing business.
The terms of a private contract are not law, and business owners sometimes can’t be persuaded to follow the rules. The most hardheaded will argue with you and refuse to accept credit or debit for small purchases, even when confronted with chapter and verse of the applicable agreements.
You can report them to the credit card companies, and after a series of complaints, Visa or MasterCard may penalize the merchant for breach of contract. The best way to fight these purchase limits, however, is to vote with your wallet and shop at businesses that will accept your card regardless of the amount you spend.
indieregister.wordpress.com 
Most people do not know what is in their CC contract, let alone their life, car, homeowners insurance/ contract. THanks for the info.
ARRRRGGHHHH! the clerk that would not accept my visa card because I was 23 cents below his 6 dollar minimum just lost my buisness, along with a follow up to the BBB and Visa.