My SIL taught English in Russia, China and Taiwan. She has a Masters and teaches at the college level in the US. Not much money in the field according to her. Depends of course on where one lives.
My son really doesn’t care about making much money, at least! He marches to a different drummer. He really wants to volunteer with Christian organizations, but he knows he has to figure out a way to support himself and thought teaching might fit the bill.
If he is just concerned about making enough money to subsist in a low-cost country, he possibly could tutor. I don’t know much directly, but from what I gather from my son, in Taiwan there is a fairly high demand for native-speaking English tutors.
DD taught English at a Chinese summer camp before she finished her undergrad degree. The pay was not great, but included room and (lousy) food.
Some language institutes train their own staff, and what they require the staff to have for previous education is entirely up to them. One place I know of used to not have a college requirement. Many of the instructors there were current college students - then again that was in the last century so who knows what their current policy might be now.
Several years ago fiona_ enrolled in a CELTA course in southeast Asia and taught at that program’s language school for several months during a pre-college gap year. You could try sending her a PM. For general information about CELTA see http://www.cambridgeenglish.org/teaching-english/teaching-qualifications/celta/
Dave’s ESL Cafe is another good source of general information about the industry. http://www.eslcafe.com/ Your son might like to look at that too.
My D is currently teaching ESL in South Korea. She was required to have a degree (hers is music) but I don’t think she has any kind of ESL certification. She teaches in a private after-school program, and they furnish housing (tiny, furnished apartment) and pay her about $2500 a month. She would have to be a certified teacher to work in the public schools.
My daughter taught English in China after graduating college. She also tutored on the side and that paid quite well, but she never could have gotten in the country without a real job. She’s another one that has never intended to earn big bucks and what they paid her in China was more like a stipend but they did pay for housing. Food was really inexpensive and she traveled quite a bit while she was there. An angle I would work at is the study abroad at college.
All three of my kids attended private colleges with good merit money and did study abroads. The only cost was airfare and money for travel or entertainment. We paid for their flight but they paid for the extras. All three have since traveled quite a bit in Europe and/or Asia. My daughter was especially interested in a college that supported study abroad and that’s something you can focus on. Some colleges, like Arcadia, offer first semester abroads. http://www.arcadia.edu/academic/default.aspx?id=3031 Goucher is another small college that places a big emphasis on global education. http://www.goucher.edu/study-abroad
You can get much more information from the following forum: http://forums.eslcafe.com/job/
I also suggest that you join the CELTA group on facebook and ask your question there. I’ve gotten tons of useful advice there before.