It's a common scam to sell flash drives with modified firmware that causes it to report a larger size than the underlying flash chips provide. Usually once you write past that point, the writes will loop around or drop the data entirely. It's likely that the $17 flag drive you linked to is a scam.
Beyond that, flash drives tend to have low write durability and horrible performance on large writes (because of poorly implemented garbage collection).
Beyond that, flash drives tend to have low write durability and horrible performance on large writes (because of poorly implemented garbage collection).