ZenCart, was initially based on osCommerce code but has developed dramatically and is a fully independent product. Known for its long list of added features, ZenCart is PHP-based and uses a MySQL database and HTML components. Its frequently praised gift certificate module allows merchants to create, distribute and manage digital coupons.
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Also server-based software, ShopSite is widely considered one of the easiest solutions to set up and run. Its Pro version (cost: $1,295) took the number one spot in Shopping-Cart-Review.com’s 2008 ranking of popular shopping carts. ShopSite is also available in less costly Manager (for stores with 15 products or more) and Starter (for stores with just a few products) versions, and a monthly payment option is available. ShopSite supports PayPal payments.
X-Cart’s major selling point is its combination of a 30-day trial period/money-back guarantee and free technical support for first-time buyers. That can help tame the fears of those uncertain about paying for shopping cart software. PHP template-based with open-source code, X-Cart may be harder to install than some other choices, so its free tech support, forums and knowledge base provide valuable assistance. Its license fee is $229 for the Gold version and $575 for the Pro version.
All choices offer a range of features and links to sample sites running their software, so it’s a good idea to evaluate the products by experimenting with the carts on those sites. An even better idea to think hard about the unique needs of your store before beginning the hunt for a shopping cart provider.
With many and varied options available, finding the most appropriate individual choice will save the most time, money and energy in the long-term.
Sounds like you've already done some shopping around. Try some demos and see which program works best for you.
Good Luck and Happy Commerce!