I agree with Morgan. I'm currently in Vietnam, and I've met a lot of travelers here who are sustaining theirs by teaching English, some of them don't even have a teaching certificate (but of course better if you have one). The pay is ok, I think. I do look like a local so it's a little harder for me to land that English teaching gig but it's very possible. I've been Couchsurfing here too which is helping me a lot to lower my travel expenses.