Ecommerce websites are built to enable you and your business to easily sell goods via the internet. There are, as with CMS, free systems and paid for. Plugins are also available to add ecommerce functionality to CMS-based websites. The main thing to consider when you are looking for an ecommerce website is that it accepts the forms of payment that you need it to and that you will need a security certificate (SSL) to provide secure transactions for your customers. These can easily be bought and are available at differing levels of security. In my opinion always pay for the absolute best one you can afford. It is more important for your website to be secure than flashy.
*part of the “Get on the Net” series soon to be published as an ebook