I'm aware of this. But then if people were happy waiting, they should generally wait for a flash sale, not to try to save $5 off a cheap PA plugin.
Anyway, I'm just illustrating a point - the s/h market is slow for the cheap/old PA plugins because there's very little money to be saved in general. It doesn't mean there aren't bargains to be hard, but the savings are small when the sales prices are already super-cheap. The pricier/newer plugins there's usually more gains to be had if you want to play the game...