To understand what that means, consider that credit and debit card transactions travel on several different networks. When a merchant accepts a charge from a card, that merchant pays an interchange, which is a fee of about 10 cents, plus approximately 2 percent of the transaction amount. The interchange is made up of a variety of smaller fees paid to all the different companies that have a part in the transaction: the merchant's bank, the credit card association and the company that issued the card. If someone pays by check, a different network is used, one that costs the merchant less but moves more slowly