They are rare at the gun shows I've been to in the last few years--tags have had $700-800 on them. No idea how much wiggle-room are in those pricings.
There's demand greater than supply, which will argue for higher prices.
19 Aug 88, I paid $302 for my Camp Carbine. CPI calculator tells me that $302 is presently worth $686, so, there's maybe $50-100 of "scarcity value" in current prices.
Now, if Ruger brings out a new (improved, on supposes, too) Camp Carbine, those values may drop (other than the cachet for an 'original' Marlin).