Whoever ends up buying this, be aware, this is most probably some sort of scam imo.
Most Pax KEYS were used up with CS:GO being so far in beta and most give-aways have ended. In order to gain access to the beta you need a gift which you get from being invited to the game, however the screen shot only proves he has the game himself.
Of course I could be wrong, but the fact he totally ignored me when asking for proof doesn't go down well.
I would say avoid this person.