We had one of those mail-order 1-meter x 1m square soft sided ones for a while (grey'ish w/ blue highlights). Fairly compact, foldable, seemed decent. Parents-in-law got one too. After ~10-11 months of use my wife was in it one day and there was a weird smell. So she started getting out. Suddenly a fire erupted from the junction box area!! holy crap. Managed to unplug it and put out the fire. Went over the next day to the PIL place and their JB was all blackened and evidently had some issues. We never used them again, and we never were able to get a refund nor legit response from the company. DON'T GO CHEAP OR MAILORDER!!
We now have a dry Sunlight Spas infrared sauna, almost big enough for 2 smaller people. My wife just loves it (although doesn't use it often enough IMO). I don't do saunas. Got it lightly-used off Kijiji after inspecting it thoroughly. Easy enough to take apart and put together if you're slightly mechanically inclined. Think we paid about $5-600 used for it, they're well over $1k new.
https://www.sunlighten.com/saunas/si.../signature-ii/
Indoor Sauna Experiences & Recommendations
