CMS= content Managment system
Can I suggest maybe buying an e-commerce system. There are many free ones out there, but if you purchase one, you will have access to tech support, even if you have to pay for it. Even though you generally don't need a lot of support, its nice to know its there if you need it. The free systems come with great forums and all the "searchable" help you need, but nothing beats being able to speak to the people who made the system. I use a few different ones on different sites, but have really found the Cubecart is great. Its simple (relatively
). There are a lot about, so research what your needs are.