Cheapest, running or swimming. If you want more of a club atmosphere, boxing, football or something would be good.
Try squash or racquetball. Lots of intense, stop-start bursts of activity, just like a hardcore interval training session. Make sure you play with someone around your own level though, otherwise it won't be much fun
Running is probably the most popular and effective sport to lose weight. If you're talking about team sports, then I'd probably say basketball. Constant running and sprinting for short periods of time. Also soccer.
According to me Marathon or Swimming are the best game to lose weight as it needs lots of physical exercise
No doubt that swimming is the best way to loose extra weight. But it seems to me that any active sports like football or basketball and so on is good for this.