An
ebay seller has a meh copy of RF28 still stuck to part of the wrapper for sale. It is creased and doesn't include a company canx (value on these are mostly tied to the canx), and he is asking $40 plus $5.62 shipping.

I have quit arguing with
ebay sellers - I just send a message with the correct ID and SCV and move on with my searches through the wastelands searching for goodies.
So I send him a quick message: "Scott catalog RF28; 2026 cat value 80 cents."
Just received his reply: "Not worth shipping it for 80 cents. I over price everything in case a collector wants it or I miss a rare valuable one. Stamps can be tricky to appraise."
A quick look at his current auctions indicates he is at least consistent in his pricing scheme.