Summary of Slot Machine Buttons
Bets one coin from your credits to play a single row. On a multi-coin machine, use this option to specify the exact number of coin plays you want, without making a maximum coin bet. You can only use this option if you have credits on the machine.
You can bet one coin from your credits during play by:
Clicking Bet One (when it is lit).
Pressing the letter B on the keyboard.
Choosing Bet One from the Actions menu.