Hi, I've got a group membership at the Racquet Club Gym on Thong Lo with 3 more slots available. It's very big, with a lot of machines, and not crowded at all, unlike most other Bangkok gyms. A year-long membership costs 12,000 baht total, and if after 6 months you decide that fat is beautiful and you love yourself just the way that you are, you can sell your membership if you want. They also have:
Tennis courts
two large swimming pools
sauna
Thailand's largest indoor rock-climbing wall
badminton courts
squash courts
Racquetball courts
and snooker
give me an email if you're interested, but call soon! I'm almost out of slots.
-LJ