Okay, this slip-up happened in the episode when Gerald was selling the Whacko Watches. You see how he walks into the arcade with TWO quarters, goes up to a machine, inserts his 50 cents and starts playing. Notice how he starts playing another game and then another, and another until he's got about four games going. If you watched, he didn't put any money into the other three machines, he just started playing! I think the creator or whomever draws the cartoon was tired and didn't watch what he was doing.