The following is a great method to get plenty 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, go outside of the Casino and save your game. Then, re-enter and head 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, then repeat if you want more money. If not, load your previous save and try again. You can make more than 100,000 chips with this method.
Save your game and head into the casino. Fight Golem battles as much as you can and acquire at least 500 chips. Once you acquire the chips, save your game, then re-enter the casino. Play Bingo and put all of your chips on it. Multipliers make Bingo the most lucrative game to play, and if you lose, simply shut your game off and reload your old save to try again. Doing this will net you more than enough chips to buy each and every item in the prize menu.