Each online slot machine is set to play a certain coin denomination -
$0.25 coins, $1 coins or $5 coins. If you put a $120 Casino chip in a slot machine with a $1 coin setting, your coin credits will be 120.

Betting
To play an online slot machine make a credit and click the spin button to spin the reels.

The reels will spin independently and then come to a standstill in a random way on various symbols that make up the Pay Line (the horizontal line running across the reels). If the reels stop at a winning combination according to the payout table, on the machine you win in line with the pay table.

https://tri.ethics3.pantheon.berkeley.edu/slot88/