Credit Card Surcharge
From Consumer Wiki
Civil Code Section 1748.1 states that no retailer may impose a surcharge on cardholder who elects to use a credit card in a transaction in lieu of payment by cash or check (but the seller can give those who pay by cash or check a discount, provided that the discount is offered to all prospective buyers).
Any retailer who willfully imposes a surcharge and who fails to pay that amount to the cardholder within 30 days of written demand is liable to 3 times the amount at which actual damages are assessed.
In addition, the cardholder would be entitled to recover reasonable attorney's fees and costs incurred in the action. A cause of action under this section may be brought in small claims court, if it does not exceed the jurisdiction of that court, or in any other appropriate court.