As you probably know Lonely Planet China, Rough Guide to China and Frommer's China are three major travel guide books. All three of them are really good and also very useful. The only thing is they are not that cheap either. However they have been very generous and re-printed large portions of their guide books and put them on-line so everyone can find a lot of useful information (and fairly reliable, too) on their web sites.
Here are the links to their web sites where you can find useful information on budget travel to China:
*** Rough Guide to China: http://www.roughguides.com/website/trav ... 84784_0006
They also have one free pdf file from the Sichuan chapter of the book: http://www.roughguides.com/images/other ... eBoxes.pdf
*** Lonely Planet China: http://www.lonelyplanet.com/china
List of the Cities: http://www.lonelyplanet.com/china/places
China dos and don’ts: http://www.lonelyplanet.com/china/trave ... es/42/1252
*** Frommer's China: http://www.frommers.com/destinations/china/
Planning a Trip: http://www.frommers.com/destinations/ch ... 10002.html
The Best Small Towns and Villages: http://www.frommers.com/destinations/ch ... 20855.html
The Best Temples & Shrines: http://www.frommers.com/destinations/ch ... 20923.html
Cities and Regions in China: http://www.frommers.com/destinations/ch ... l#subdests
They also have special editions for Beijing, Shanghai and Honkong:
Beijing: http://www.frommers.com/destinations/beijing/
Shanghai: http://www.frommers.com/destinations/shanghai/
Hong Kong: http://www.frommers.com/destinations/hongkong/
Really a wealth of information! Enjoy!