Lots of variables.. condition, numbers, year, markings, finish. I've seen them sell for between $1200 for a piss poor shooter example to well over $6-7k. The stock and holster if repro, they are just that...200-250 for those. Every part should have a number down to the firing pin, one mismatch number or part supposed to have a number and doesn't, the game can change drastically. And beware, should you shoot it, and break/loose a numbered part, poof, goes the value and your pride, I have a mismatched junker to beat on because of that..
When I bought my LP.08, the seller allowed me to tear it down and do a visual inspection prior to purchase. I do own quite a few Lugers...and before you jump in, and due to the amount of funds, defiantly research before dropping the first coin, SKS, whatever..... look at it, tear it down, take pictures, ask questions, ask more questions and research some more. I've seen an experience where a person didn't use research and use good judgement and over paid....to the tune of around 2 grand... for something that was nothing in the end, all sales final........and no, it wasn't me.