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.
One of the best slot apps that pay real money has to be the FanDuel Casino app, mainly due to the excellent selection of slot machines that they have available at the gaming site.