I purchased a brand new Schwinn Airdyne(used once by an 80 year old) for about $200 on FB Marketplace. Its a fan bike that also has levers that you push/pull with arms for a much more full body workout than a Peloton. Resistance adjusts instantly based on how much effort you apply. 15 minutes of HIIT consisting of warmup, 20 second sprint, 1:40 rest for up to 7 rounds. Perhaps one of the most effective cardio and fat burning workouts in existence.
However, it sucks. By that I mean, it will be one of the most difficult and challenging workout modalities you've ever done. It's also, as stated, one of the most effective. One thing that I have found to be true is that whatever kind of exercise one chooses to do, it HAS to be something you enjoy. Otherwise there is no way to stay consistent long term. Anyone can force themselves to do something they hate short term. Therefore I have concluded that the best form of exercise is the one that you will actually do. If it takes a $2000 Peloton plus another couple thousand in subscription fees over time, its better than the alternative(extreme couching). Personally, I take the route of the Airdyne for 15 minutes 2-3x/week, coupled with some resistance training. I don't want to be skinny and weak, since skinny people don't live as long as overweight people. My BMI is at the top end of overweight but my body composition is much better than most, and I look like pretty normal person, i.e. no one would ever look at me and think overweight, or giant bodybuilder(I'm not), let alone borderline obese.
I also like that the Airdyne fits very well into the world of frugality and Mustachianism. Bought it used so no newly manufactured "stuff", cheap, and will last basically forever.
Perhaps this is another option for those that want to cycle for overall good health and improved body composition. The Airdyne will, IMO, provide better results than a Peloton, with the caveat being that you have to be willing to use it.
On the more non-Mustachain side of things, I've been seriously considering buying a C2 rower. If I ever do, I'll probably buy it new since the used ones I've seen aren't much cheaper than new. It's another fantastic piece of cardio equipment that offers significant full body strength benefits as well, and doesn't suck anywhere near as bad as using an Airdyne.
I have asthma which has previously been well controlled but is lately becoming much more troublesome. When I was young and ran slowly for a long time almost daily(forced, when in the military for two years), my lungs became drastically stronger and my asthma all but disappeared. I hate long, slow cardio and will never do it consistently on my own, so Airdyne, rowing, sprints, high intensity sports such as racquetball for example, are my go to. I also bought a jump rope. I haven't quite gotten a routine down yet, but its a goal.