Tony's fitness gym on Soi 19 behind T21. I bought a pass yesterday. 500 baht for 1/2 month or 900 baht 1 month. No daily prices, no AC. There is a power rack, dumbbells pairs up to 100, though it's not a full set, some dumbbells are missing. It's pretty hot in there, but I'm glad I can still hold a barbell and dumbbells during my time in BKK and not lose the gains.