I have noticed from both working at the gun shop and selling stuff on Gun Broker that Carbine prices are down. Recently I have seen mix-masters for $1000 to $1100 again. Last year, the cheapest were around $1300 and up.
Surprisingly, retail prices for M1 Carbines in Commiefornia are also down. MIni-14s get a higher price here than even clean carbines in northern Commiefornia. That may partially be that M1 Carbine ammo has been largely unavailable to dealers in Cali since the pandemic, and Cali residents can't order ammo online because of the Draconian efforts of our totalitarian overlords.