I bought a 1940 Nazi-marked 8mm Mauser 98k sporter rifle from a really desperate seller today for $200. It's, unfortunately, in pieces. So I'll be putting it back together as best I can based on plans I found on Google.
I'll post pictures when I get it rebuilt or when I get pissed and throw it into a big pile on the floor. I found its serial number on the 98k registry, and it was an issued rifle used in WW2 from the Mauser factory in Berlin, which is rare, so if I can get it pieced together and functional it should be worth upwards of $1500.
It should be worth more, but the guy I bought it from had it drilled and tapped for a top-mounted scope, instead of an angle-mounted scope, which would make it period correct, so he took off about three grand from the price.