A Powerful PHP Shopping Cart Software
Avactis is a powerful PHP shopping cart application that has multiple versions (including free + open source) and impressive features. It has everything and more to expect from an e-commerce tool on every level from product to member managements, orders and marketing.
The application is very flexible in creating any type of promotions like discount codes, price-based or quantity discounts discounts, built-in affiliate system, newsletter management and more.
SEO is taken care of -mostly- automatically with SEO-friendly URLs, optimized HTML code or breadcrumb navigation and more can be done with the help of custom meta information and titles.
Avactis works with almost every popular payment processor including PayPal, Google Checkout, Authorize.net and much more. Simply, Avactis is a complete software for creating and managing an online store. And, besides the paid ones, it also has a free version.
Get the free version: http://www.avactis.com/free_shopping_cart.php