Store Front & DB Editing?

I am currently working on a site which has its visitors purchase access to a series of videos. I don't want to handle the payment processing any more than I have to (mostly because I'm scared...lol) and I can't seem to find a storefront which has this sort of thing built in.

The way that I'm seeing this, the user would select the product on my site, and then be redirected to a store page, which will handle the payment processing. The result of a successful payment would then be a change in my DB to reflect the user's new purchase.

Does that sound like a good way to go about it, and how can I do this? I have no idea even where to begin on this, so ANY sort of guidance, however small, would be immensely helpful.