Avoid buy Fake cheap SD MMC card, USB storage Drive on ebay.
How to test
If you find very cheap SD MMC, USB storage drive on ebay, such as 1G SD card bid only 1.2GBP. Please donot hurry to bid it down. Because what you get maybe 64M only.
The fast way is to copy 1G file to the card, and paste it on another computer, if the file could work well. The card maybe the 1G truly.
Please use Paypal on ebay, because you could get your money back if it is fake.
Some fake cards makers gave us negative votes for this guide. They are scared.
Our way is effective!