Jigoshop is one of the original e-commerce plugins for WordPress. It is a complete e-commerce website solution for selling products with WordPress. Jigoshop is a free plugin with many paid extensions (and themes), made both by the Jigoshop team and third-party developers. The extensions include several payment gateways, marketing tools, media plugins, translation and shipping.
The website has a demo to give you an idea of what the plugin is capable. Try it for free then install the free or paid add-ons that you need for your online store.