In my opinion, the market for the products listed above is already big enough. You will have to compete with website such as: Ebay, Play.com, Amazon.com, Dabs.com and many many more. And lets face it, you're going to have a tough time trying to outsell companies like those.

Try to think of something original, something that you can't buy from many online stores (I know it's hard, but if you really want to sell a product, it has to be something that they can't buy from elsewhere).