Magento (community edition) is a free open source shopping cart started by Varien in 2007. Magento impresses with its extensive feature list. Most functions which need to be added on with other carts come as standard. Itís ideally suited for companies who need a professional online shop presence.
highly flexible coupon and pricing functions
comprehensive filter functionality (filter products by)
multi-store as standard
ability to create and edit orders in admin
large number of high quality modules via Magento Connect
no need to hack core code
impressive template system
Magento sometimes gets a bad press for being too complex and server resource-intensive. Both are fair comments, but should not put you off considering Magento. With the right developers on board and a high-end hosting environment, Magento can provide extensive functionality at open source level.
Zen Cart is an open source project started in 2003, based originally on osCommerce. Zen Cart impresses with its realiability, solid feature list and ease of use, making it ideal for shop owners who intend to handle development themselves.
includes all standard features to sell online
easy to understand templating and PHP structure
suitable for coders beginning with PHP
light footprint making it very accessible for shared hosting environments
active development team
That Zen Cart has been around since 2003 however shows in its PHP coding structure. However this downside is exactly what makes it accessible to beginners in PHP and makes it an ideal first cart for new coders.