Another idea would be to charge table fees normally per round, and tack, say, a $40 per team "prize fee" into the first entry. Prize money would come exclusively from this pool. First place gets the prize pool, final round loser gets their card fees back in free play tickets, or some such. This would make it scale fairly for any size field, since the total prize money would be proportional to the # of teams and the money spent. In a 10 team bracket, it would be, say, a 1 in 10 chance of winning $400. In a 100 team field 1 in 100 chance of winning $4000, etc.