If you're playing for fun, then just go to the casino and have fun. Chat with other players and have a good time, just like you would if you were spending an evening out with friends at a restaurant or movie. You have to pay the restaurant, you have to pay the theater and you will most likely end up paying the casino. It's the cost of a fun evening.
If you plan to spend 2 hours there then take enough to cover 2 hours of minimum bets and no more than you can afford to lose. Don't plan on making money. The house always wins with Roulette.