Am I charged a fee when a credit card payment declines?

When a payment declines, you are charged what's called an authorization fee plus any pass-through fees the card brands assess during a decline. So, the cost to you is typically less than 20¢ on the high end. If you would like to pass this fee through to your customers, you will want to create a charge item and call it "Failed Payment Fee" or something like that. Then, when a payment is declined, you can add that fee to the account.