Remember, this is not an arbitrary requirement that ebay is imposing on us sellers. When a potential buyer looks at your chip pictures, he has the option of seeing an enlarged scan. You really want him to see the chip in as much detail as possible as this avoids later problems when he thinks your chip is a different one, or maybe is in better condition than a 1x scan would show him.

It costs you nothing other than a bit more storage on your disk if you like to keep history of what you have put up for sale on ebay. My 400 dpi scans all upload to ebay in a couple of seconds so that's not a concern.

If you're using Epson Scan software, select 400 dpi in the box called "Resolution".