Go on htfr.com, and look for the "Numark TT1625 battle pack", you get 2 decks (direct drive),a mixer,headphones,needles,speakers and all the leads and bit and pieces.
im 21 and ive been using this for a couple of years now, perfect starter pack!
i think you get some vinyl with it aswell
The whole bundle costs around £265.00
I got mine about 2 years ago
djstore.com
arrived next day
It is a good package to start off on, then upgrade the speakers and mixer when desired. But as he is only 13 you could probably research and get cheaper decks, depends on how much you want to spend, as long as they are direct drive