I didn't want to tip my hand on my personal thoughts too much, but KD is spot on with two of his recommendations.
Dollar tickets are perfect. (I wouldn't discount for volume purchases at a dollar a piece, dollar per is cheap enough) He is right in that volume works.
Big buyers like holding long snakes of tickets (use the ticket rolls with the keep this ticket, tear off and deposit the match pair style. Choose red ticket color. You want these to be showy) half of the fun of being a "big roller" is showing off and hyping it up.
The second advice about giving each player one "included ticket" with event entry is also key. Now everyone is in and will be there to hear the draw... And to be there to look at the big rollers... Which is what the big rollers want.
Hype it up. Make it fun. Point out the big ticket buyers and work them against each other in a fun way. Make them want to outdo the others next time.