Give me feedback on my business idea?

Ok so I'm 15 and my idea is to bulk buy some skins for a range of digital devices (xbox one, ps4'iphones, blackberry, computers and tablets) these skins would be almost a kind of tattoo that is stylish on a device, I would sell them using cost plus pricing

Alternatively, what about a disc repairing service it would have to be very cheap and I'd have to buy refills often

Who will you sell to and why would they buy from you? What would your profit margin be? Who would supply you?

A vague notion isn't a business - but it's a starting point.