Most online shoppers use credit cards to pay for their online purchases. But debit cards - which authorize merchants to debit your bank account electronically - are increasing in use. Your debit card may be an automated teller machine (ATM) card that can be used for retail purchases. To complete a debit card transaction, you may have to use a personal identification number (PIN), some form of a signature or other identification, or a combination of these identifiers. Some cards have both credit and debit features: You select the payment option at the point-of-sale. But remember, although a debit card may look like a credit card, the money for debit purchases is transferred almost immediately from your bank account to the merchant's account. In addition, your liability limits for a lost or stolen debit card and unauthorized use are different from your liability if your credit card is lost, stolen or used without your authorization.

Other electronic payment systems - sometimes referred to as "electronic money" or "e-money" - also are now common. Their goal is to make purchasing simpler. For example, "stored-value" cards let you transfer cash value to a card. They're commonly used on public transportation, at colleges and universities, at gas stations, and for prepaid telephone use. Many retailers also sell stored-value cards in place of gift certificates. Some stored-value cards work offline, say, to buy a candy bar at a vending machine; others work online, for example, to buy an item from a website; some have both offline and online features. Some cards can be "reloaded" with additional value, at a cash machine; other cards are "disposable" - you throw them away after you use all their value. Some stored-value cards contain computer chips that make them "smart" cards: These cards may act like a credit card as well as a debit card, and also may contain stored value.

Some Internet-based payment systems allow value to be transmitted through computers, sometimes called "e-wallets." You can use "e-wallets" to make "micropayments" - very small online or offline payments for things like a magazine or fast food. When you buy something using your e-wallet, the balance on your online account decreases by that amount. "E-wallets" may work by using some form of stored value or by automatically accessing an account you've set up through a computer system connected to your credit or debit card account.