Other than the rare nickel slot machines (which only exists in old school Las Vegas casinos), the best payout comes from the $5 slot machine, according to the Las Vegas Review-Journal. Casinos had a 5.46% win percentage in 2024. In comparison, theR$25 slot machines had a 5.86% average when it came to casinos winning.
While you can lose your money faster with high-roller slots, the payout percentages are always better (on all slots regardless of the denomination) if you get the maximum amount on each spin. The most fruitful games, when it comes to odds and cost, are the nickel and quarter slots.