Completely agree with Rajadeep. All you have to do is get a comparison of prices of phones across various sites.
Ebay prices (for Manf warranty products) will generally not be the lowest. That is due to the fact that you have to pay Ebay almost 6%. Plus let us not forget the Listing fees. To get eyeball, you need to put up more than one listing. In Bold, Standout, etc. Costs bucks.
Ebay is a decent platform for low price high margin products or for products not generally found in big stores for cheap.
Like Big Boss said,
smartphone and
tablet accessories have a huge market, plus great volumes and good margins. Especially for products not available by the bulk. For example, I bought a silicone case for
Samsung Y Duos Lite for 60 bucks in a wholesale market the other day, while it retails for about 120-150 on Ebay. So its a great profit. Plus since the phone sells a lot, u might get good volumes too.
Check
THIS.
What you can do is try out Ebay as a seller without opening a shop. Get your near and dear to order accessories and simpler stuff through your listing. Do simple listings without any add-ons and the listing cost would be about 3-4 bucks for 30 days. Get a good reputation on and only then open a shop. Having a shop needs you to pay shop fees regularly. Don't waste that straightaway. Start off selling simpler things directly without a shop.