To get 50 FREE Chuck E Cheese Tickets you just need to play the game. They also have other games you can play to earn free tickets. One free ticket reward certificate can be redeemed per child, per day.
You can also Sign up Here to get coupons emailed to you. Be sure to join the Birthday club as well, you will get FREE tokens for 1/2 year and on your Birthday month also!
(Thank You, Brandon!)