There are a number of E-commerce platforms available these days in all the technologies you can think of. Be it Java, PHP, .NET, etc, there is an E-Commerce platform which is serving the businesses as per their business requirements and budgets.
The latest trend these days is closed based e-commerce platform. These are good in the way that you do not need to install anything on your machine, do not need to buy a server and pay some infrastructure guy few bucks from your pocket. All you need is an account on these cloud based platforms and you are ready to step in the exciting world of E-commerce.