I'll preface by saying that it is not 100% unsafe to buy USB drives or SD cards from eBay- I have bought genuine cards before and there are legit sellers of such products. I bought 2 genuine Micro SD cards about 3 months ago- not only did both pass tests, but I've had each one filled to capacity with no issues reading anything. However, this is now the second return of a faked device I've had to initiate this month.
I bought a generic MP3 player with 32GB flash storage, H2testw reported it was 16GB genuine, 16GB fake. I returned it and got a refund. Last week I ordered a 32GB Sandisk Ultra Micro SD- after it vanished into USPS tracking limbo I got impatient and bought a Samsung EVO at Walmart instead. Good thing too, the card showed up in today's mail and it's 8GB good, rest bad. Though the fact the card lacked the advertised Android software the package claimed was my first sign that things weren't right. In both cases the sellers had reputable feedback scores. I now have to try and go through the returns process again- and it is highly unfair of eBay to ask us to send back fake devices rather than requesting they be destroyed with photographic proof(I suppose some of you are familiar with Paypal requesting a very expensive violin to be destroyed!), because you just know the seller will put it back in their shop.
This has been a known issue for years but it seems to be increasing in frequency. Even Amazon seems to have fallen victim to these fakes because buyers report getting faked devices and cards when buying directly from Amazon.
I want to say it's worth it to pay more from a local store so you know you're getting a genuine device... except I get paranoid, knowing Amazon is stocking fakes, and I wonder how long it will be until Walmart, Target and other retail chains start stocking fakes as well. Are they ordering direct from the company or a 3rd party supplier?