VISA

Minimum Purchase
Can merchants set a minimum purchase or charge a fee for using my Visa card?:
 * "Visa has certain regulations that all merchants that accept Visa cards must follow. One of those rules is that Visa merchants are not permitted to establish minimum transaction amounts, even on sale items."
 * "If you run into a problem like this with a merchant, please notify your Visa card-issuing bank. Visa member banks have access to the appropriate Visa rules and regulations as well as to the Notification of Customer Complaint forms which should be used by the bank to document and file merchant complaints."

Minimum Purchase:
 * "Visa merchants are not permitted to establish minimum transaction amounts, even on sale items. They also are not permitted to charge you a fee when you want to use your Visa card."
 * "If you run into a problem like this with a merchant, please notify the financial institution that issued you your Visa card. These institutions have access to the appropriate Visa rules and regulations and can help you document and file your complaint. You'll find their address and/or telephone number on your Visa statement. Their telephone number may also appear on the back of the card itself."