US might be different, we originally set up through our bank. They charged 3% I think. Then I had a Chamber of Commerce membership and through them it was 2.5%. We were using a hand held machine and run a roller over the card to do a bill. Now we have an electronic device hooked to phone line and all we do is swipe the card and it does authorization etc. I think it is through Monaris.
Check out
www.monerisusa.com to get more info. It allows us to do Mastercard, visa and Amex.