If you exercise care and research you can buy genuine Kingston and Sony USB Flash drives on eBay. You need to do your homework first! While listings for on branded false capacity usb Flash drives are going down on eBay, the issue of counterfeits for these two brand names has as yet, not been addressed.
Please review the information presented to help you find the genuine capacity items for both Kingston and Sony usb flash drives on eBay.
See: Fake Sony 32GB 64GB 120GB 360GB 500GB Micro Vault USB Flash Drives Available on eBay! to help identify the packaging and also what Sony has to say on the subject.
For suspect Kingston usb flash drives please review these articles presented at Fake Memory Sentinel on Ebay to help you recognize the models and the packaging. Kingston has a new higher capacity usb line now. It appears that the older smaller DataTraveler models are being reprogrammed and repackaged to higher false capacity sizes. These are counterfeits. To help you please examine the Kingston site for their models and also the colour coding.
See: Meet The DataTraveler Family and DataTraveler
Unfortunately stamping on shell casings for size and any serial numbers – do not seem to guarantee that the item is genuine. The only sure way is to test your drive using a software such as H2testw 1.4
On eBay the lime green and purple rimmed tend to be the false capacity models. The advertised size when tested is the actual size these drives were meant to be (2GB, 4GB). You can tell the genuine from the fakes easily for these models. The genuine items are correctly advertised with the sizes reported by Kingston, the fakes are not.
Always consult the manufacturers site for either Sony or Kingston before bidding or buying these brand names on eBay for USB Flash Drives. It will help you to find the genuine flash drives from these brand names.
Fake Flash News - Internet & eBay Fraud 
kittyfireflash
May 27, 2009
Please report into sosfakeflash on your seller for evidence. see http://sosfakeflash.wordpress.com/report-a-fake/ It is important that they know who the seller was.
Michael
May 27, 2009
I purchased just a few days ago (May 2009) a 32GB Kingston DataTraveler 150. I was immediately suspect as soon as I opened the blister pack because the plastic casing felt cheap and thin. The LCD activity light was non-functional and copying 12GB of mp3 files reuslted in errors galore. Upon further inspection and via a phone call to Kinston Technology, I determined the drive was a counterfeit. It did not have any laser etching identification on the USB plug.
I filed a claim on PayPal and left negative feedback to the seller.
These people should be thrown in prison for this fraud. They messed with the wrong guy. I will be pursuing this vigorously.