OsCommerce was a true Opensource eCommerce package, which back in the early 2000s became a great choice for e-commerce web development. We liked the fact that it was built using PHP and was extendible to our needs, I believe it was one of the first OS cart systems to employ PHP. It's great that OsCommerce is being revived by a new development team and we are waiting for version 4 in anticipation!

osCommerce (or rather its newest version, 4) has a lot of features that will be suitable for small, medium, large / enterprise, and even global businesses. It is free for its core version that on its own brings a lot: a fast shopping cart with a good checkout experience, sales and marketing tools, customer manager and order manager (including edit orders), support for multiple sale channels, advanced back end, many shipping and payment solutions, and more. Then come the apps, all 250+ of them. Free and paid, depending on what the business requires, they are easy to install via the back end. osCommerce is mobile and SEO friendly too and can be scaled up to support databases with 1,000,000+ products and customers, and many thousands of orders a day.

The cost is a big reason we use osCommerce. The platform is open source and doesn't cost anything to implement, aside from our work time and external hosting costs. osCommerce has familiar shopping cart designs that are relevant in today's e-commerce world. Though there aren't a whole lot of high-quality templates compared to other services that require payment, there is much more room for customizing the templates.