Don't know if you're referring to providers. Of course, as anywhere else in the world, just depends on how much you're willing to pay and how much the provider is willing to accept.
For normal GFs, it depends on what you have going for yourself. The prettier, more educated, and wealthier background that the girl is, the more difficult she will be to pickup. Most Chinese women aren't stupid and are very pragmatic in terms of getting involved with a guy (especially a foreigner). You would have to be of the same stature or above for a quality woman and fall within her goals. She also has to answer to her family too. Meaning if she decides to get involved, she's thought it out, and will give it up (might have to teach her a few things). Like Dragon, my SO is from the PRC (college grad and will earn 6 figures shortly).
It is a misconception that Chinese are poor and uneducated. Simply because of the sheer scale of population (PRC 1.3 billion, Taiwan 23 million) and economy, there are now far more wealthy and educated Chinese in China. Probably true when compared to the majority of other countries. Of course, there are also far more poorer Chinese in China. The uneducated, unconnected, and poorer ones have limited options to pursue. Those may be easier to pickup if that's what you're thinking but they probably won't know any English. The highly educated ones get English started in middle school.