At the last couple of gun shows the M1 carbines were everywhere. On dealers tables and people carrying them around. I had never seen so many up for sale, I didn't check prices.
I suspect it is due to ammo. It's not common to find anymore and it's normally not cheap. Back in the days when the Carbines were inexpensive there was plenty of surplus ammo to go along with them but those days are over. I usually pick up some of the steel case Herters stuff when I stop in at Cabelas in KC. It can often be had for about $14\50.