WordPress.org

Author: Ecwid Team

Ecwid is a free full-fledged shopping cart that can easily be added to any blog. It offers the performance and flexibility you need, with none of the hassles you don't.

There are seven key advantages to Ecwid:

• It's SaaS
• It's free
• It takes minutes to add to your site
• It supports drag-and-drop
• It has AJAX everywhere
• Upgrades are seamless
• It requires little to no technical support

You can see the demo there: http://www.ecwid.com/demo-frontend.html

Full list of features: http://www.ecwid.com/features.html