Slot machines vary payout percentages. Some machines pay out more than others. Whether it’s a penny, nickel, or dime slot, the ratio of payout depends on the machine. Some places have regulations on payout percentages.
The dollar slots often have to be programmed to pay out at a higher percentage, to make up for the faster rate of loss that these bigger games have. Which game you prefer should depend on your bankroll. If you want to stay in the game long enough to hit a jackpot, you should play at stakes that you can afford.
If you only have $50 to play, and you want to play for a couple of days, you should be playing the penny or nickel slots. You can rise in stakes levels as your bankroll gets bigger.