Clams are another notable mention. I remember getting good sized and good looking maxima clams for $50-75 in the 2010 timeframe. Small ones have been selling for $100-150 for the last 5'ish years.
I've found that zoas are about the same, some really high and some really affordable. Montis seem to be cheaper, ditto for a bunch of good looking Acros. It's not that Acros are cheap, it's that interesting Acro availability has increased and there are a lot of $20-40 frags that would have been $50-80 a few years ago.