I will give my personal opinion here. Demand for teachers in China is relatively high and on daily basis the demand keep increasing due to the increasing demand for English proficiency as a requirement for hiring Chinese for jobs. The demand is for Persons who are native english Language Speakers or those with good western accents. This placed a lot more pressure on Parents to make sure that their wards get the best out of Education by insisting their wards are taught English Language. As a result of Chinese One Child Policy, Children get the highest attention from both parents due to the fact that they the only children at home. To the extent that some parents hire teachers to teach their Children one-on-one basis. There is a myth out there which deters others from venturing. I will also not just put it out there that the there is no incidence of cheating or scams these are evils in every society but it is good to note here that it is rewarding to be a teacher in china. It is only individuals who are in a hurry to make money and will not take time to recruit the teaching offers due to desperation that get cheated. It is also a fact that guanxi ( Social Connections) is a necessary social capital in china in order to succeed.
I Visited China 2 years ago on an internship program organised by a chinese company, where I got addicted to Mandarin and I wanted to learn it. I therefore returned to china again just to learn the language then I met a lot more agents who paid me like 130 RMB ($21) and as a student, I managed it till I completed and applied to my masters in World Economics on Chinese government Schorlarship which I got and had another teaching job paying me so well. I wont put the figure out there but if anyone cares to know, they can check up on line or better still, ask any friend living in china.
You need to visit china first and tour the place, know the people well, establish good contacts and be ready to learn. then you can come back again to make it big afterall it wont cost much. sometimes good connections could even get an individual all that is needed to comfortably stay in china without going through all the forth and back experiences I had.
This is my advice. Just play your cards well and Bingo !!!