Here's a great method to gets lots of Casino Chips easily. It involves the initial accumulation of a lot of chips (around 2,000). This can best be done by doing Golem Battles in the Casino.

After you have around 2,000 chips, head outside of the Casino and save your game. Then, reenter and go to the roulette table. Put 100 chips on as many numbers as you can, covering enough to give you a 50% chance of winning more chips than you sacrificed. If you win, take your earnings, go back outside, save, and keep going if you want more money. If not, load your previous save and try again. I made more than 100,000 chips with this method, so it works.