Various Trademe members have comment that there are listings for very cheap 128GB, 256GB and 512GB USB Memory Keys appearing on the site. Please be aware that there is a large number of fake USB Memory Keys being sold on eBay in the USA and from China which the firmware in the drive has been hacked to overstate the capacity and it looks like they are now starting to turn up on Trademe. And they’re likely to turn up in other places too such as street markets.
Signs to look for a genuine 512GB USB Memory Key retails for over $1000.00 and any drive of this capacity will be USB 3.0. The fake ones are priced much lower and commonly USB 2.0.
These are fake USB Memory Keys / Sticks, not USB Hard Drives. Genuine USB External Hard drives with capacity of 500GB to 2TB etc, are a lot cheaper than a 512GB USB Key. So if you have purchase a cheap USB External Hard Drive it is probably OK.
But if you have purchased a cheap, large capacity USB drive I strongly recommend you run tests on the drive before using it to store any critical data. There is lots free testing software available such as H2TestW for Windows.
These drives will report the capacity as stated in the Listing i.e. 512GB in the operating system, but will corrupt the users data and fail when they reach the true capacity of the drive. The seller may not even be aware, but the buyers data is at risk as soon as the drive reaches it true capacity (normally less than 8GB).