Every player must stick to his bankroll. Bankroll is the total amount of money you can afford to play with or to lose. There is a bet max button on every slot machine. Bet Max button allows you to play with the maximum bet on this very slot machine. Comp is so called additional bonus, which is given to the player who has been playing one and the same slot machine for quite a long period of time. Comp can be represented by free meals and in come casinos by money rewards. House edge is an amount the casino is mathematically guaranteed to win over a long enough period of play. If the House has an edge of 5 percent on a particular game, they will win five cents over every dollar played at that game over a long enough time. Payback is the reverse of the House edge for slot machines. The payback is how much a slot machine gives back for every dollar it takes in. If a machine has an 85 percent payback, it pays out 85 cents for every dollar it takes in; therefore, the House edge on the machine is 15 percent. Ideally, a slot machine you play will have no worse than a 90 percent payback, especially if you play slots online.