The last few years CrossFit type gyms are the ones that have flourished at least in the US (there are many other gyms that offer similar training such as Iron Tribe, etc). One chain of gyms that has really evolved and taken off is Anytime Fitness. AT has become one of the fastest growing mid-size gyms/fitness center in the world. I’m not sure how low cost of a gym is an AT center bad it’s not as high as one of the huge fitness centers like “Lifetime”. Another chain of fitness centers that has evolve is Orange Theory. They seem to be doing well also. Both AT and OT are franchises.