OpenCart - A free shopping cart system. OpenCart is an open source PHP-based online e-commerce solution.s

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.

PrestaShop - Create your online store with PrestaShop's free shopping cart software. Build an ecommerce website for free and start selling online with hundreds of powerful features.

Shopio - Shopio is an all-in-one hosted shopping cart solution.

WooCommerce - A freely available eCommerce plugin that enables shop facilities on your WordPress website. Functionality enabling extensions & beautiful themes available.

Selz - Seriously Simple Selling