A Shopping Cart program allows you to implement your own on-line storefront. The shopping cart keeps track of what visitors have ordered and allows them to add or remove items from a 'virtual shopping cart'. When a visitor decides to check-out, the order information including the buyer's name, address and billing instruction is e-mailed to the site webmaster and a receipt is sent to the shopper. There are many pre-written Shopping Cart script that you can customize for your use. Most offer demonstrations and extensive documentation are available.