Some quick tips to help avoid fake SD Cards/flash media

another trick you can use in linux with gnome. It takes a minuet though.

1. Destroy all partitions, and remake the MBR.

2. create a single partition the entire size of the disk.

3. get the size of your disk from the file manager.

4. make truecrypt container(s) up to the reported size.

5. copy them to the flash device.

6. Hash both the originals on your HD, and the copies on the flash drive.

If the hashes match, your flash drive is as big as the computer says it is.
I've heard of people buying counterfeit Sandisk SD cards. Personally, I usually only buy Transcend brand, as they are just as good and don't seem to get faked. I only buy from Amazon (itself, not 3rd party sellers), Newegg, or a brick and mortar store like Wallmart/Best Buy.

I buy quite a lot of SD cards, but so far have not been burned.