It is rough getting into these days. I know inflation as a whole is part of it but I remember when I was first old enough to start buying the weapons of world war 2 seeing a G.43 for $900.00. Granted I did not know anything more than what it was, no clue of condition and if it was a scarce variation etc. but wish I grabbed it!
As mentioned above, $1600-$2000 should be more or less fair these days on a shooter. Just take into account you will probably sink a few more dollars into it for springs and a piston or any parts you decide to replace.
My shooter sniper is a non matching AC45 I got at a show for $1600.00 After parts and working on it was more like $2200 with a repro stock, shooters kit, bolt housing and repro mount. I could have got a nice matching example for the same amount. Still, these are the guns you have fun with and you can't really assign a dollar amount to that.
Best of luck finding what you are looking for. These are tremendous fun shooter or not!