Thanks for your well intentioned post; however, anyone who accepts a postion for any amount, regardless of their degrees or experience, less than 6,000RMB monthly is grossly underpaid.
Your advice regarding negotiations, though, is right on the money. Never be afraid to negotiate. But these things should be non-negotiable: Free apartment - Western style. Internet connection paid for. Computer provided. Any amount of time over 18 hours a week to be paid as overtime. Electricity and water paid for - although, I think it fair for your employer to ask that you pay for electrical useage that goes above a certain level.
Furthermore, before accepting a position you should be quite certain of the location of the apartment you will be provided. Many teachers have found themselves housed in slum areas. Try to get a picture of the apartment, the neighborhood and the school before accepting a position.
Make informed decisions. Seek testimonials. Do your research. If you do all of these, you can have a truly rewarding and memorable experience as a teacher in China.