osCommerce is a free, feature packed eCommerce program that provides everything you need to get your online store up and running in a very short time. There are no fees or costs to use the program. osCommerce is an Open Source based online shop e-commerce solution that is available for free under the GNU General Public License. The front side of osCommerce that customers see, is a professional looking web site, and it's appearance can be changed to look the way you want it to. The back side of oscommerce is the administrative section that completely handles your products, customers, orders, and online store data. It also has a community of users at osCommerce contributions that develop and contribute enhancements that can add more features.

osCommerce uses PHP scripting language and MySQL database server, and will work on any PHP 4.1+ enabled web server running Linux, Microsoft Windows, Solaris, BSD, and Mac OS X. osCommerce has been in operation for over six years now, and is used by thousands of online stores worldwide. The pre-installation, and installation instructions in the documentation that comes with the download are fairly easy to understand.

Here's a long list of features. If you're already sold on osCommerce, you can skip down to the post installation notes below.

Administration / Backend Functionality:
Supports unlimited products and categories....Products-to-categories structure....Categories-to-categories structure....Add/Edit/Remove categories, products, manufacturers, customers, and reviews-Support for physical (shippable) and virtual (downloadable) products....Contact customers directly via email or newsletters....Easily backup and restore the database.... Print invoices and packaging lists from the order screen....Statistics for products and customers....Multilingual support....Multicurrency support....Automatically update currency exchange rates....Select what to display, and in what order, in the product listing page....Support for static and dynamic banners with full statistics

Customer / Frontend Functionality:
All orders stored in the database for fast and efficient retrieval....Customers can view their order history and order statuses....Customers can maintain their accounts....Addressbook for multiple shipping and billing addresses....Temporary shopping cart for guests and permanent shopping cart for customers....Fast and friendly quick search and advanced search features....Product reviews for an interactive shopping experience....Forseen checkout procedure....Secure transactions with SSL....Number of products in each category can be shown or hidden-Global and per-category bestseller lists....Display what other customers have ordered with the current product shown....Breadcrumb trail for easy site navigation.

Product Functionality:
Dynamic product attributes relationship....HTML based product descriptions....Automated display of specials....Control if out of stock products can still be shown and are available for purchase....Customers can subscribe to products to receive related emails/newsletters.

Payment Functionality:
Accept numerous offline payment processing (cheque, money orders, offline credit care processing, ..)....Accept numerous online payment processing (2CheckOut, PayPal, Authorize.net, iPayment, ..)....Disable certain payment services based on a zone basis Shipping Functionality....Weight, price, and destination based shipping modules....Real-time quotes available (UPS, USPS, FedEx, ..)....Free shipping based on amount and destination-Disable certain shipping services based on a zone basis. There are many payment gateways options.

Tax Functionality:
Flexible tax implementation on a state and country basis....Set different tax rates for different products....Charge tax on shipping on a per shipping service basis.

Post installation:
Once you get osCommerce installed on your web server, the installation notes will continue to guide you through the remaining setup. Then the PDF documentation that comes with the oscommerce download, will guide you through the configuration of your administration settings.
When you're all finished, you'll have a functioning eCommerce web site. Good luck with your installation and your business.