I just completed several eBay transactions as a buyer and I have yet to be completely satisfied with any of the transactions that have been completed. In the majority of the cases, the problems were minor such as scratches or writing in the manuals which were not anticipated. In a couple of cases, I received calculators with dents and scratches even though I asked specifically if there were any visible defects to the calculators. It seems that the onus is on the buyer to make sure to ask enough questions to determine the quality of the product rather than the seller providing a reasonable description. I see this as a major problem because it is much easier for the seller to notice defects and report them than it is for the bidder to ask a lot of questions in the hope of confirming the quality or uncovering a problem. But by advertising anything negative about the product, the seller detracts potential bidders so the descriptions are positive and vague in nature.
Unfortunately, in the case where I questioned the seller about the apparent defects, the response was that the item was previously owned by someone else and that the seller did not know much about the product. (This did not answer my question.)
I have also noticed sellers using words like "unused", "like new," or "mint" inappropriately or do these words have a different meaning on eBay than common english usage. There is an ad on eBay for a mint calculator but there is a picture of the front of the calculator with dents visible on the plate below the display.
It's buyer beware when doing business on eBay. Unfortunately, eBay is the only readily available source of HP calculators at high prices.