I am Thai, speak Thai , can also work in Thailand. However, if I'm living on pension $900.- I will not choose Thailand as the place to retired , unless I want to live in a temple as a homeless one who just needs enough food and shelter. You can recieve free medical care from every teaching hospital/university including dental works, and most 10-30 beds hospitals. Nevertheless, it will drive me nuts to be in this beautiful country without the means to go around, see things, and eat delicious food. I agree that spending $900.- in Vietnam or Combodia would be wiser spending. If you can get around the VIsa problem, you can survive in more remote places of Thailand- No BKK, Pattaya, Chiangmai, any big city. Try Pangha, Krabi, Lumpoon, Srisaket, ect. And you can rent a room from locals instead of an apartment or a house.