If a user needs to make a purchase or other transaction within a site, it is much more convenient for them to make all of those transactions at the same time instead of one after another. Therefore it is very attractive for a web site to have a CGI program such as a shopping cart to remember information for a user, which they can access for a transaction at the end of their session with the site.

Example
Try the shopping cart form below; it will calculate a running total of all of your purchases and let you continue to "shop" from a list of available items for as long as you like before you decide whether or not to make a final purchase.

Select Items
Product	Price	Quantity
Widgets	$25.00
Gidgets	$75.00
Gadgets	$58.45
Total: $