Simpson's or Phoenix Investments have interesting Lugers in that price range...
You could also bid on consignments in the auction houses, too...
Then there is Gunbroker, AuctionArms, and GunsAmerica...
Personally, I prefer Gunbroker...It's an online auction, but there are some really good deals fairly often...
I'm always looking for a decent Russian Contract Luger...
Edit: If you are overwhelmed in what is being offered, then our own For Sale Forum is your best bet...
