Value all depends on where the Luger is located and what people there are willing to pay for it. For instance, where I live the price is about 50% less than in the USA and in Bulgaria it seems as they are worth a lot more.
This is a good exsample of the Luger value where I'm located (seller thinks it's a Walter P38 btw);
http://www.finn.no/finn/bap/object?finnkode=16837507 3500kr= 543 USD