Convenience fee

Credit card processing companies ordinarily forbid charging a surcharge for accepting cards, but, under limited circumstances, they do permit a convenience fee. The rules vary by company, but in general, a convenience fee is allowed when payment by credit card is an alternative form of payment not ordinarily accepted by a merchant or service provider. For example, when you pay your income taxes online by credit card, expect a convenience fee of 2 percent to 4 percent of your tax payment.