I've taught in Thailand for about two years, both as a volunteer in the mountains and as a private school teacher as well. If you're thinking about staying in Bangkok, you'll find opportunities that make well more than you need to be well off in Thailand. That comes with a toll, as the high wages come with a price that I wasn't really okay with. English isn't spoken regularly at all in the grand scheme of things in Thailand. Thai culture gets in the way of learning, because people just throw money at private schools, forcing their cute little kids to learn three different languages and to me, I had the experience to really see the rich kids bully one another. You won't make first world income as you branch out to smaller cities and villages, but I promise you, I think what we are looking for outside this money cog is love for people and compassion to share with the people around us. Small town folk will be happy to spend time and share their lives with you because money was never the most important thing in their lives. I hope you find what you're looking for in Thailand, and that Thai becomes a language you decide to learn too :)