Buff's are my favorite American coin. I put together many sets over the years; principally with well-matched, half-horn, full date coins. My pride and joy was completing a full horn set. I was constantly on the prowl at shows, seeking Buffs that met my criteria. Although I owned some overdates and three-legged coins, I wasn't that much interested in the mint errors.
There was a dealer, now deceased, who was always trying to promote the two-feather errors. His prices were high, I thought, for these relatively minor and fairly common errors. Over time, I found a number of them, including a few 1921-S's. I took a handful of them to a show, wherein this dealer typically attended. He appeared to have the same pieces in his case that I'd been seeing for at least a few years. I offered to sell him my pieces for about 20% of his retail price .... Just as I suspected, no sale.