Ruby and Sapphire have upped the ante on their two games now. The first is the basic slots game from Red and Blue: insert however many coins you want (1, 2 or 3, which add more rows on the slots where you can win prizes) and try and line up the same picture.
Three Red or Three Blue 7's: 300 coins
Three 7's (any mix): 90 coins
Three Azurill: 12 coins
Three Lotad: 6 coins
Three Pikachu: 3 coins plus Pika Power
A cherry: 2 coins
Replay logo: free game
If you manage to charge up your Pika Power, you will enter into "Reel Time" where you have more control over the precision of stopping the slots. Do note this is a difficult feat to accomplish.