Assessing the Return to Player (RTP) Percentage. When choosing a slot machine, the RTP percentage is an important metric to consider. This number shows how much monefree rummy cashy players typically get back from a slot machine over time. A slot machine with a 95 percent RTP, for example, should eventually yield $95 for every $100 wagered. Selecting slots with higher RTP percentages can increase your chances of making money even though no slot machine promises instant wins. Examining Features and Themes.