I would think that a good attorney to verify the legality and to draw up the terms and conditions should be your first stop. An assurity bond, an escrow account, a 3rd party to assure security among other things may be required.
A lot depends on your state, in Georgia it has to be a non-profit and have permission from the local sheriff. I've been involved in a dozen or so car raffles, $100.00 per ticket, usually 350 tickets max, for a car with a net cost of $18-20K. An attorney friend of mine won a new BMW convertible last week! $80K+ his tax bill is going to be stout on that!