to buy a mobile phone the best place I can suggest you is this bitcointalk forum.. the best thing of this forum is we have lots of trusted and reputed escrow. who can help use to complete buy sell sucessfull without any risk. but other sites don't have that much safety. they ask you for upfront payment no matter if you receive the product or not.
Indeed on bitcointalk there is sold a lot, I think that Bitify can also be a solution by the way because its a safe method and on that website is sold all kind of things..