One of the shopping cart programs we use at Evolve Systems is Ecwid. Ecwid is an enhanced performance based shopping cart with incredible flexibility. It is easily installable and will work on multiple platforms including Facebook and mobile devices. Your business will have the ability to accept purchases from nearly any device.
Ecwid just released update 6.2 today, which includes improved order export, minor bug fixes and improvements, as well as a few new in-store and back-end translations. These updates join other features such as shipping for international standards and payment systems, multiple payment gateways, and analytics data such as customer and shipping IPs in the back-end.
If you are looking for a strong stable shopping cart, Evolve Systems recommends Ecwid.