As noted in the post above, I emailed the Dayton director to see what difference in attendance low-fee vs. no-fee produced. I also asked him if he thought the "traveling trophy" they award to the winner at the freerolls makes a difference as to whether the winning player comes back next month. Here is his response:
...Attendance at our $10 entry fee tourney is better than the free roll tourney, but not by much. Each have had 8 tourneys this year so far, and we have had 8 or more players more than half of the time at our $10 entry fee group (approximately 5) and 8 or more in less than half of the free roll events (about 3). Most of our players play in both, but two players have never played in the $10 entry fee group and indicated they do not want to play for money. I don't believe the trophy helps that much with players returning. If they take it home, they do return the next month (except in one occasion that I recall). If they know they cannot return the next month, they do not take it home. Also, I believe the players are happy with the $10 entry fee and do not want to see it increased. I truly believe we would lose some of our players if we raised the entry fee.
Bottom line, our attendance is not that different...just a few more at our money events.