OpenCart - A free shopping cart system. OpenCart is an open source PHP-based online e-commerce solution.s
Dynamic Yield - Personalization & customer experience management
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.
Optimizely - A/B testing you'll actually use.
WooCommerce - A freely available eCommerce plugin that enables shop facilities on your WordPress website. Functionality enabling extensions & beautiful themes available.
AB Tasty - AB Tasty is an all-inclusive platform for conversion rate optimization, personalization, customer activation, and testing.