Many moons ago, when I had started having thoughts of working abroad, Japan was attractive. While the JET Programme offered the best salary, the large eikaiwas offered decent pay. You wouldn't get rich, but you could pay your bills, travel around Japan (or SE Asia), and maybe even save some money. You could live comfortably.
The Fukuoka General Union has recently published a video of how one ALT lived in Kitakyushu. It's an eye-opener and a must-see video if you are thinking of ALTing. The pay all but ensures that you'll have to have a second job just to make ends meet. While this is only one person's story, I think it translates well across eikaiwa. Be aware of what you're getting yourself into. If you find yourself in this situation, do you have the means to get out?