As this article points out, merchant agreements with credit card processors specifically prohibit merchants to have minimum purchase amount requirements for credit card use. This applies to gift cards as well. If they say you need to meet the minimum purchase amount, tell them it is against their merchant agreement. If they still refuse, report them to MasterCard, Visa, or American Express.

Of course, it’s not really the merchants fault. They have minimum purchase amounts because for small purchases their fees end up being a much larger percentage of the overall price and they may lose money on the purchase. However, if enough consumers complain about merchants, perhaps enough merchants will complain about the credit card fees, which are what really need to change.