Gambling is not a good alternative for earning extra cash. Each game you play at a casino has a statistical probability against you winning. Slot machine odds are some of the worst, ranging from a one-in-5,000 to one-in-about-34-million chance of winning the top prize when using the maximum coin play.
Yes/No betting is simply betting for or against an outcome or statement. For example, Will Man United beat Liverpool? , and then the punter bets yes or no against the given odds.