If you are planning on buying a USB card reader be very carefull. It is very hard to fing one from Hong Kong or China that actually works, I have gone through many of them as have people I know and only two have worked so far.
If you are going to buy a USB card reader I suggest you either make sure there's a good refund policy with no catches or buy one from a UK seller. But beware, due to the language barrier it usually takes a long time to return a product and get a refund or replacement.
NOTE: This guide isn't written to be offensive to Hong Kong or China sellers, this is merely based on mine and my friends experience with the USB Card Readers.
If this guide bothers you or if there is anything you would like to add please contact me through eBay or by email James@Teletek.Co.Uk.