There is a  professional classroom at Jin Ling Rd No211, (Subway line 8 Da Shi Jie station).
And they could also offer lesson at home, both of them are private 1-on-1 lesson, each lesson to be 90 min. long.
We also have different package for different instrument, if you want play guitar or bass or drum in a band, the basic package is enough for you (5 lessons)
For piano, they also have different packages for different requirements.
The tuition fee is 200 RMB/90 min. and  give receipt for the tuition fee.

Contact information:
Charles Colpain
Email: colpain@hotmail.com

I agree with the above answers....another avenue that you can look for guitar lessons that may offer free lessons is a church or bible study group. We had that back home and I've seen quite a few of them in China. If you can find a group with a guitarist they may be able to give you free lessons and you can toss out the fee. Just be a regularly attendee to the services or group and have them set aside a couple of hours of free guitar lessons. There out there you just have to look!

Guitarshanghai is offering professional guitar classes, too. The teacher is Julia, a German guitarist, who is living in Shanghai since more than 10 years. So she can teach you in Chinese, English and German languages. Julia studied the classical guitar at the Academy of Music in Stuttgart Germany. After finishing the Academy of Music she was working at a Music School in Germany for several years before she moved to Shanghai. She is still practicing the guitar, always learning new stuff and so she is still able to make performances. Even if her guitar level is very high, she loves to work with children and young people and she is able and willing to teach every level - from the beginner to the advanced.