The Casino is unlocked on experience level 7. It costs 0coin and 0gem to open. The location of the Casino is in the City. The purpose of the Casino is for players to be able to win coins and gems. When making 500coin bets, there are three possible wins: 600coin, 1000coin, and 15gem. Due to low returns, it is generally not recommended to ever place lower bets.
Place 500coin bets until you get 15gem. Since the June 2017 update, winning gems in the Casino has become harder to achieve.
Note: It will be harder to hit 15gem on a day when Cooking Fever has reduced prices or other specials.