[QUOTE=RichardInSF;13784218]

In China, when you buy anything like this, you ask the merchant to demo it before leaving. They will all be set up to prove to you in that case that you are getting what you paid for. You will also be in an area with a zillion little stands selling the same thing, so you can ask around and find how low they will go. These people tend not to rip you off to the same extent that they do in tourist areas, you typically will not get hyper-inflated prices.
QUOTE]

Very good points and absolutely true. When buying anything in China, it is customary to take it out of the box or package right there and test it out, whether it is a memory card, cell phone, electric hair dryer, etc. In fact, the merchant will think you nuts if you don't!