Do I want one?

What should I look for?

What price range should I expect to pay?

THANKS I advance

Do I want one?

This is a difficult question to answer as I don't know your wants, what you already own, use case, etc.

That said, I will give you my impression as an MP40 owner.

I have a lowly Charles Erb MP40 "tube" gun built off a German kit.  Looking at MP40s from a shooters perspective its not a bad gun.   I picked up my MP40 not because I really wanted an MP40, but because a good deal presented itself and I already had a pile of different subguns so  why not try something different.

On the plus side, they have a controllable rate of fire, are fairly robust in construction, simple in design, and in my experience they are reliable.  They are also somewhat iconic with the older over 65 crowd who grew up watching a lot of WW2 movies and TV shows, but many younger folks have no idea what it is vs. say an Thompson or even an MP5.  Most of my gen-x peer circle who are all in their mid-40s had no idea what it was when I first brought it out to shoot.

The downside is that original magazines are pretty expensive (~$150), the sights are not great, parts don't necessarily grow on trees, barrels are rare/expensive if you damage one, they are not really upgradeable or reconfigurable to any extent (not real way to put an optic on them- granted would you want to), they have a pretty heavy trigger pull, like all open bolt subguns you get that first round "lunch" as the bolt slams home,  and are full auto only (may or may not bother you).

Would I buy a MP40 as my one and only machinegun...I would not.  There are imho better options out there in my estimation, especially in the original German pricetag arena.    As example, the original german receiver MP40 guns cost as much as a non-Colt M16 which is a better in just about every category.

However, if you have a good collection of machineguns and you want something different in the WW2  subgun category an MP40 is not a bad choice.  I would probably go for a USGI made Thompson over an original German MP40 for just slightly more money if asked to pick, but if you are looking to round out a collection of WW2 guns an MP40 is a nice addition along with a Thompson, Reising, M2 carbine, Grease Gun, PPsH, etc. in the subgun category

What should I look for?

Assuming you don't care about matching numbers.

- I would look for one that does not show signs of a of a former significant deactivation/reactivation procedure where the barrel, bolt or receiver may have been damaged.

- Does it have any ugly PD or reactivation markings where somebody engraved/hacked their name on it with an electro-pencil.

Other than that I would just look at the wear/tear on the gun.

- Check the bakelite lower receiver for any signs of cracks.
- How does the stock fold and how much play/wobble does it have,
- Scope the barrel signs of pitting or rings/bulges from a former squib round.  (barrels are expensive and difficult to replace)
- If you can take the gun apart, check the collapsing firing pin spring tube for signs of damage or wear as this part seems fairly delicate to me.
- If the gun has a sliding/safety cocking handle, does it still function properly, are the detents in good shape, and/or is it loose.  (this part also seems like it is fairly delicate and/or susceptible to wear to me)

What price range should I expect to pay?

My impression, is that you should expect pay  in the upper teens ($17K to $19K)  for a non-matching original German receiver MP40.  Add a thousand (or two) if the gun coming from a reputable dealer and maybe subtract a grand or so coming from an individual.

Seems like the all matching numbers original German MP40s run in the low 20K range  and the tube guns (Erb & Wilson) in the lower teens ($13K to $15K).  Non-matching German guns fall in between this range but closer to the matching guns price range than the tube gun cost range.

Overall, I hope this is helpful and good luck with your MP40 purchase.

My first machinegun was an MP40 registered during the amnesty period. It was all matching serial numbers. Paid the sum of $500 for it.

It was a peach to shoot.

Things to look for:

Is the bolt face smooth and free of pits?

Extraction. Check the extractor to make sure it is free of chips and has correct spring tension.

Barrel-is it free of rust, pitting, dark spots