Pricing up "What are slot machine odds?" starts with the stake per spin. Penny slots and progressive jackpots sit at opposite ends of the same machines. One promises a small stake, the other a huge prize, and both are less simple than they look. What a penny slot really costs per spin, how a jackpot meter grows and what the odds of hitting it are decide whether either is worth playing, and neither rewards a strategy the way their fans expect.
Penny slot payout rates are usually lower than those of higher stake machines, because operators set a lower return to player where stakes are small. Penny slots still exist in large numbers, though they look like any other video slot, with bright themes, many lines and bonus features rather than the single coin slot of old. Whether they are worth it depends on treating them as entertainment; how to win on penny slots has no answer beyond luck and a firm budget.
Progressive jackpot odds are long, often one in several million spins on the largest networked games, and many require the maximum stake to qualify. The biggest jackpot on a slot machine can reach a sum that changes a life, which is exactly why the base game usually returns less than an ordinary slot. Whether progressive jackpots are worth it depends on accepting that cost for a small chance. Free slots with a progressive theme pay no real jackpot at all.
Set a budget before the session and treat the jackpot as a rare extra, never as the reason to keep playing.
Rarely. The coin is a penny, but the stake per spin is the coin times the lines times the bet level, which often comes to far more.
On some machines only the maximum stake qualifies, or it raises the chance; the rule is in the game's help screen.
A small share of every stake on the linked machines feeds the meter until someone wins it, then it resets to a seed amount.
The largest linked jackpots are won at odds of many millions to one, and their size is exactly what those odds pay for.