9. osCommerce Online Merchant
This free offering gives storeowners tools to manage both the front-end catalog and back-end administration. It provides a basic template layout structure to customize the product catalog. The Administration Tool lets merchants configure the online store, insert products for sale, manage customers and process orders. Released under the GNU GPL, osCommerce Online Merchant is supported by a large community of more than 256,000 storeowners, developers, service providers and enthusiasts.