Hi Tim, and welcome to the forum.
As you start acting on your interest in the Luger pistols, consider studying first. I call this "Luger University", and it involves identifying one of the eras that you're particularly interested in (Pre WW-I; WW-I; Weimar era; WW-II; Post WW-II) and obtaining the reference books on that era. This will help you understand what is "correct" about Lugers of each period for a given manufacturer.
If you're partial to beautiful pistols, consider the Swiss manufactured Lugers. They are remarkable. Bobba's book on Swiss Lugers is available directly from Italy at a reasonable price. (see
Abe Books online for a connection to the "DEA Store" in Italy). It's under $51.
Luger collectors value pistols most highly in their original factory state. That means that any wear; alteration; refinishing or restoration reduces the value of a Luger pistol. Rarity can trump this in some cases; but doesn't end up pushing the value of a restored pistol above that of an original. Of course, this can help you obtain a variation at a lower cost - just don't expect it to appreciate as a more collectable one would.
There is nothing like inspecting an original high condition collectable Luger in person. The photos can't communicate accurately things like finish appearance. For that reason, I like to attend shows that are geared toward firearms collectors. At a recent collector's show in Salisbury NC I was able to examine several from different eras, and get a good idea of how original condition Lugers should appear. Do this any time you can.
At regular gun shows in my area, I see the majority of Lugers overpriced for their condition, and / or misrepresented. It's easy to make a mistake. For that reason the reference books are a great value if you're serious - even at the apparent high cost.
If it's true that the upcoming George Sturgess book will be available on DVD at $35 a copy, get one - it's a bargain. (Simpson's will be selling the book sets).