Most countires around me require a degree. I don't know about China, but I THINK in China, one can get a job with only a high school diploma. I have no desire to teach in China (too many nightmare stories), so I haven't checked. I KNOW in both Thailand and in South Korea, degrees are mandatory.
In Thailand, the TESOL is supposedly required as well, but many teachers here teach on fake TESOLs. Some even teach on fake master's degrees. Thai authorities don't check really. I'm also sure there are many teachers here teaching on fake credentials all around--TESOL, bachelor's, even master's. I myself have a real bachelor's degree in English and a real TESOL. After two years teaching, I can say honestly that getting a real TESOL wasn't justified. Given the apathetic students I've seen so far, coupled with the antiquitated education system here, I know now I should have gotten a fake. Sure, I learned some cool things in my TESOL program, but that hasn't justified getting it. Perhaps if I taught middle-class American students, the students EVERYBODY wants to teach, spending 1500 USD on that piece of paper WOULD have been justified. Who knows, I may land at a job in the future where I at long last DO get to use what I learned at my TESOL program.

BTW--South Korea doesn't even require a TESOL, yet Thailand DOES. And South Korean jobs pay TWICE or even three times as much as Thailand teaching jobs, so the 'rules of thumb' don't always apply. Keep doing your homework, and always get second opinions on what you really need. Don't spend a lot to get into this. The flight overseas will already cost you
a bundle. Play it smart about it and you should be fine. You can also check out another TEFL website located at www.tesall.com .

Good luck.