I would like to begin by stating this is a very general comment and of course there are some reputable items from China.
However, you should always proceed with plenty of caution when buying things from China.
China is great at faking things, like many countries but having spent a year living there i can honestly say the fakes really are often as good as the real thing, but many times the fakes can also be lousy.
In China its not so easy to get a card style account like we have here, in general thins isn't that common procedure so paypal style accounts are usually out. That means you might be asked to do a money wiring or transfer....its much harder to track these and you should really consider what you are buying before hand.
When buying electrical items of a large value i.e laptops, cameras etc please don't be fooled by extremley low prices. In my experience electircal items are not that cheap in China (mainland).(and yes i had people buying for me it wasn't just they wouldn't give me the cheaper price) Yes they are a bit cheaper but not significanlty so if something seems far too cheap don't be fooled into the notion that in Asia things are cheaper by amazing lengths. However electircal items from Hong Kong come under different rules because of the way China and Hong Kong seperation.. Electrical items from Hong Kong are usually cheaper than mainland China and many travel over if they can to buy such items from there.
The range of fakes covers a plentitude of things, from small to large...be it jewellery, handbags, trainers, dvd's, or right up to musical instruments or electricals. Do not always expect Western quality as in general although many things are made in China, Chinese people do not have access to them.
Like i said this is a very general guide and i mean no offense but just want to share my experience with you. If you ever go to China you can buy the most amazing fakes but you won't be paying the real price!
Best of Luck!