To get a Retirement Visa for Thailand, you need one the below (or a combination of both):
- 65,000 bt of verified monthly income
- 800,000 bt deposit for 2 months in retirement visa application
65000 bt is about US$ 2000, and 800,000 bt is about US$ 25000.
So, in fact it is not so cheap to be able to get a visa to retire in Thailand.
The general living costs are not very high if you live in the villages, in the capital a beer can cost around 4 dollars.