I wouldn't, only because I've heard too many stories of extra chicks, special prices, guaranteed pullets, chicks in need of a new home... etc etc all turning out to be cockerels. If the guy isn't a personal friend and you're not likely to ever see him again, expect boys or at least straight run, which leaves sex to total chance. People will unfortunately say anything to get rid of extra birds.
Why not buy sexed chicks from your local farm or feed store? I've had very good luck getting my pullets from those places... they get them from reputable hatcheries and I don't have to buy a minimum order or pay shipping.
