Stores are violating their contract with the credit card companies if they set minimum or maximum charges, or force you to show ID in addition to your credit card (with the obvious exception being for age-limited purchases). Depending on your state and your card issuer, surcharges or “convenience fees” may be banned as well. The best way to straighten these guys out is to report them to the credit card company. People who have done so on the Credit Boards message board say that when they report a merchant, they get a letter from the credit card company and when they go back to the store, the shenanigans have stopped. Here’s all the contact infos for the credit card companies to file a merchant complaint, as well as links to merchant agreements, in case you feel like standing up for your consumer rights. Someone better warn Amy’s Ice Cream!