My friend worked as a cage supervisor and he told me all about the cashier job description because I was curious about working with him. Apparently you just need a GED and you must be able to get a license to work in the casino. These are usually issued by something like a regulatory agency such as the casino control board or commission in your state.
They will run a criminal background check on you and the casino is generally responsible for training you. I honestly think the pay isn't that high, but it's the tips that can really make your day. I heard one person was pulling in an extra $50-$100 a day in tips alone.