Yes, but you have to do some manual work. Create a non-inventory item called "CC Surcharge" or whatever, and if you like, you can map it to a special income account. Now if you would like to charge 3%, you should put the price at $0.03. When you ring up the sale, note the subtotal, then add this item last. Now, take the subtotal dollar amount and enter it into the Qty field for the CC Surcharge item. This will do the automatic math for you. Here is an example of doing a Service Charge at 4% -
Cheers!
Peter Eastvold
BlackRock Business