nopCommerce is the leading ASP.NET based open-source eCommerce platform. It is a free solution with comprehensive features that is applicable for all types of users from new online businesses to the most demanding enterprise-level eCommerce experts. nopCommerce is one of the most secure, stable and extendable shopping carts. The platform has a rich architecture with lots of features available out of the box. There is also a lot of additional functionality that one can find in the marketplace. Free support on community forums is available.