I saw someone pay $55 EACH for Magpul mags.
When that original ban hit, I had a bunch of brand new S&W 9mm mags for the various high capacity S&W pistols. Those mags were really valuable as they would fit a bunch of guns including the Daewoo, the Marlin camp carbine, and the Star model 30 etc.
I was in grad school at the time and tried to sell them at a reasonable price. I can recall going to gun shows and seeing dealers charging $100 for their various high capacity mags who would not give me $30 for mine. $30 was actually a couple of dollars less than they had retailed for before the ban.
There were a lot of dealers who would not deal unless they could absolutely skin you.
I actually still have those mags, never was able to sell them. I did trade one dealer even for a Browning Hi-Power mag. He was actually not even a dealer, just a guy who had a table.