XoopsEC is open-source EC system since 2013. You can build a on-premises service for E-commerce. I designed UX as the amazon, yahoo shopping essence a lot. This package is contain with the XOOPS Cube 2.2 CMS and EC module and CreditCard payment sample. Pay-Pal peyment will be soon.

Apache2.0(mode-rewrite) / PHP Ver5.3 (or later) / MySQL5.5 (or later)

Live Demo site : http://www.xoopsec.com

Document (Japanese right now) : http://dl.dropbox.com/u/31666676/xoopsec.pptx

(Bit older, update will monthly) http://www.slideshare.net/YoshiSakai/xec-bmcart

Any comment and question welcome. https://github.com/bluemooninc