OpenCart - A free shopping cart system. OpenCart is an open source PHP-based online e-commerce solution.s
Allomani - Allomani is an E-Store with the shopping cart for online shopping websites, hosting & designing, Paid services, etc.
Gumroad - An all-in-one solution to sell your work and grow your audience.
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.
Sellfy - Sellfy is an easy to use but powerful e-commerce platform where you can sell digital, print on demand or subscription products. Use a Sellfy storefront to create a beautiful online store or embed a Sellfy shopping cart to your own website.