Already have a merchant account with your brick-and-mortar business? Then simply take the credit/debit card information received online and process the card manually via your existing merchant account. No additional account is necessary for Web transactions.
Processing cards manually gives you the advantage of being able to hold the card information and charge customers when their purchase ships. Most people don't like to be charged for something they haven't received yet; the automated card processing on websites does just that, transferring funds from customers' accounts within hours or a few days, rather than when the order ships. Remember, though, that if you're not able to ship the product within 30 days of the order, you must notify the customer of the delay [source: Federal Trade Commission].
If you're not sure a merchant account is the way to go, there are alternatives such as PayPal and ProPay. These types of companies handle the checkout and payment processes for you, meaning no merchant account and associated fees. You have to pay for their service, of course, but the fees will be less. PayPal, for instance, offers a transaction fee of 2.9 percent or lower plus 30 cents per processed transaction, but no monthly fees (as of May 2015).
Besides processing credit cards, you may wish to accept electronic checks, or e-checks. Customers wishing to pay via e-check input their checking account information into your site, and your payment is pulled from their checking account and deposited into your banking account through the ACH process. You'll need to contract with a company like Authorize.Net to incorporate this feature into your website [source: PracticalEcommerce]. PayPal and ProPay also offer e-check options.