jCart - Free PHP AJAX Shopping Cart
jCart is a very simple & free shopping cart script that is built with PHP & jQuery. It offers a base Ajaxed basket interface that can be improved further by implementing the checkout pages.
The shopping cart script is unobtrusive, generates valid XHTML & design of it can be customized easily via CSS. jCart’s inputs are validated on the server-side for a better security. There is a step by step installation guide & how-to provided that can be found here.
Requirements: PHP 5.2+
Compatibility: All Major Browsers