Some FAQs:

What is the typical payback percentage for slot machines at casinos in North America? The slots in casinos throughout North America should return anywhere from 80 percent to 98 percent of the money put into them. In Las Vegas, the average can be as high as 94 to 98 percent because there is a lot more competition among the casinos for players.

Are slot machines in certain places likely to have worse payback percentages than others? Definitely! Slots in airports, gas stations, laundromats, diners, train stations and bars almost always have horrible payback percentages.

Do casinos still use the old style one-armed bandit machines that use reels and levers? You'd be very hard-pressed to find such a slot machine in the typical casino. It's very very unlikely. Nowadays, the machines, even if they have reels, are computer-generated programs that are controlled by a single microchip.