I've had many over the years, still have a few.
You pay for condition and originality (parts, finish, ect) just like any other collectible firearm.
But a mismatched and/or refinished pistol can be an excellent shooter.
One of my best shooters as far as reliability is a mismatched upper & lower unit 1908 commercial in 9mm. Someone tinkered a bit with the trigger link in the sideplate so it could be the longest trigger-pull Luger around.
But 100% reliability w/nothing more than Rem/UMC 115FMJ ammo and a MecGar (sp?) repop magazine.
A Mauser BYF41 all matching including magazines and in 95% condition struggles to get thru a full magazine no matter what it eats.
Looks nice though.
Various DWM mfg pistols incl a 1917 Artillery all feed and function just fine with the above ammo. An occasional bobble, but they are range toys after all.
The Artillery's like to throw the rear sight tangent bar forward on recoil if the spring or detent is a bit weak. Wondering what happened to your superb pistolmanship untill you see the rear sight setting on 800m..
Magazines cause more problems in Luger pistols than anything else including ammo. The best replacements I've found are the MecGar. Fairly inexpensive and they work.
Originals are nice to have but some are hitting the century mark in age, most are 70 and 80 y/o and have been bounced around, adjusted and just plain abused over time and conflicts. They are pricey too.
WW1 pistols often have unit markings on the grip strap(s). Sometimes more than one and an old one XX'd out.
Collectors generally pay more for WW1 and WW2 issue and marked pistols.
So some of the better buys, if there are any, are the between the wars (Weimar Era) pistols. That includes those with the police sear-safety mentioned above.
The imports from Russia and former Soviet states that came into the US in the 90's are some decent shooters. So called EG VOPO Lugers among them, most are refinished and many have replacement parts including bbls that are 'force-matched' as the collectors say.
Foreign contract Luger pistols will generally be high priced collectibles. There is a wide variety, some true raritys. They were ser#'d and marked as Commercial pistols with the Country's Crest on the ring. Beautifully made pistols.
You won't find much for under $600 or $700, though occasionally a gunshow special appears for under that yet. It usually has a problem or two that can be fixed if you are so inclined.
Parts are still generally available if you search around w/FleaBay being a good source.
Some parts vary a bit from era to era. The Old Model (flat mainspring & gripsafety) and New Model (coil spring) have some very big differences obviously.
New (coil) springs from Wolff last I knew. Changing the recoil/main spring takes some thought, a bench vise and simple tools so you don't have to fight with it.
Decent wood Repro grips are avail now along with the wooden magazine bases.
The grips & mag base are not easy or quick to make if you want to make a set. But it's a good exercise for the fledging stockmaker.
Parts are not a drop-in tinkertoy type of fix for this firearm, so be prepared to be a gunsmith.
I'd stick to a 9mmLuger cal pistol if you are just wanting a range toy shooter to blast a few boxes of ammo once in a while.
The 30calLuger pistols are very nice Commercial guns for the most part. and very often priced a little less than the 9mm counterpart.
The Finn contract pistols probably being an exception in the pricing.
The only contact I've had with the stainless steel Mitchell Arms/Houston mfg pistols is through repair.
Mitchell Arms was started by a group of x-HighStandard employees. The factory doing the pistol making was Aimco in Houston.
The earlier guns seemed quite nice and little problem. When the firm was bought out by Stoeger, they started applying their TradeMark 'Luger' stamping on them as a marketing tool.
The quality seemed to start downward not long after that with the metal polish and fit being the most noticable changes. Broken small parts,,the TD and the safety levers most commonly seen with voids in the castings.
All of the parts except the pins,springs and a very few other parts were investment cast stainless on those from the start. Investment cast in itself is not a bad thing, it's just the QC over the operation that defines it.
The 70's InterArms Mauser/Luger,,to tell you the truth I can't ever remember seeing one in for a repair other than refinishing.
Some shooters had the same 'Luger' complaints at times,,FTfeed,,FT eject,,ect. But they looked like a well built pistol and some nice variations were made. I personally have never owned one but have shot a few of them w/no complaints.
Find the right ammo and magazine and most any of them will function for you.
The I/A Luger appearance rankled the collectors all up and were bad mouthed up and down as not being a 'real' Luger. That's for the collectors to settle with themselves.
We're interested in a shooter for the most part and I'm just throwing out some observations and opinions.
Everybody needs a Luger.