A convenience fee is added to a transaction when you choose to use a nonstandard form of payment. A merchant might charge you for paying a bill over the phone by credit card instead of by mail.

A merchant charges you a convenience fee when you do not use a standard form of payment, which includes cash, check or automated clearing house transfer. A credit card payment is considered nonstandard and subject to a convenience fee.

Credit card processing costs are recouped through convenience fees. Depending on the payment network, a merchant fee of 2% or more per card transaction may apply, says Experian.

"There is a cost to any merchant that accepts a credit card," says Jim Butkiewicz, professor of economics at the University of Delaware.

but they are not the same. A surcharge can be added in any situation for the privilege of using a credit card, but a convenience fee can be charged specifically for using a nonstandard payment method.

You can avoid paying a convenience fee by simply not using a credit card. Instead, you can use a standard payment option, such as cash, check or ACH transfer.

You may pay a convenience fee if you pay by credit card. You may have finances coming but not enough to make a monthly payment. Or you may get more value from credit card incentives or buyer protection than from fees.

A convenience fee could also be worth the cost if your card comes with purchase protection, price protection or extended warranty benefits.