Allomani - Allomani is an E-Store with the shopping cart for online shopping websites, hosting & designing, Paid services, etc.
OpenCart - A free shopping cart system. OpenCart is an open source PHP-based online e-commerce solution.s
WooCommerce - A freely available eCommerce plugin that enables shop facilities on your WordPress website. Functionality enabling extensions & beautiful themes available.
Selz - Seriously Simple Selling
Shopify - Shopify is a powerful ecommerce platform that includes everything you need to create an online store and sell online. Try it free for 14 days.
PayKickstart - PayKickstart is the ultimate shopping cart and affiliate management platform, empowering online Entrepreneurs and digital publishers with the tools to sell their products online.