Looking for video clip store theme

Girlfriend and I are looking to start a small online website selling small video clips and photography photos. Possibly some other stuff (All may not be downloadable) as well. We want to set up a website to do this where people can browse and buy them and download them immediately after they have purchased them. We have been looking at a number of hosting sites (Hostgator for example). Not sure how all this works. It’s really hard reading all through these templates and what they do and not sure if I can install them on any hosting platform or not??? Can someone point us in the right direction?