Scammers definetly seat themselves in the mainstream market. If you look at all the scam stories they are always with iPods, PSP's, Xbox's, Playstations.
- You make sure he has good payment methods (ideally Escrow)
- He has shipping prices to everywhere (Scammers normally can't be bothered to figure out the shipping prices all over the place)
- Ask him what the MOQ is and check it's not too high (Always good to start small with a new supplier)
- Ask for a sample product (This way you know if he actually has the product, it may be retail price but then you know he has the product and most likely legit)
- Also ask him for his whereabouts as there may be a chance he is close to you and you can just pop in and buy directly from his warehouse
Hope this helps :D