Welcome Trekker.
You are wise to ask first, not after you leap!
I'm with Ed, you should be able to buy the 6" mismatched .30 luger for under $1000; though if you "wanted" one and paid for and to have a long barrel installed, it likely would cost that much or more.
I doubt buyers will be lined up for it, but one never knows.
I have a 6" .30 that is a lot of fun to shoot
; but it is more expensive unless you reload.
Here is mine.