It seems that once again the banks do more screwing than all the SP's in the GTA, that is if the following which I found on an SP's site is true:
I do accept Visa, Mastercard and American Express which I will need ahead of time to authorize and there is a 30% charge for this method of payment with proper I.D. The billing on your credit card will be discreet and they charge me a 30% fee for this.