These memory capacities have now been superseded by capacities such as 2GB, which cost the same yet offer better value for money.
If you are looking for a low cost flash drive, and only need a tiny amount of memory, 2GB usually represents the cheapest capacity on the market.
NAND flash memory below 2GB is no longer produced by major memory chip
manufacturers like Samsung, Hynix, Intel, Toshiba and Micron in large
quantities. Occasionally we are able to source sufficient amounts of 1GB
memory and make these available to our customers, but the long term trend is
towards larger capacities.
Some flash drive producers still offer 128MB, 256MB and 512MB memory capacities. They will be using unbranded, inferior quality NAND flash which we strongly recommend you avoid as not all flash drives are created equal.