I think there are a lot more factors than are being talked about here.
1.) $7500-25000 is all a fair range for these trucks. There are a lot of factors that can go into those numbers.
2.) There is more risk in government auction trucks, thus trucks with less risk reasonably fetch a higher price. The risk is significantly raised/lowered based on your familiarity with military vehicles, your experience with FMTVs specifically, your tools/skills/contacts, etc.
3.) You could easily spend $5000-15000 replacing worn/damaged parts, installing newest parts/upgrades, etc. That doesn't even include labor. So a truck with even a modest list of things you would want to go buy could easily be worth considerably more to you.
4.) If you're a "run what you brung" kind of guy, you will have the opinion that there is less difference between the value of trucks of various states of repair/completeness/upgrade/etc. If you are a person who would feel compelled or rewarded to find all the upgrades and extras, and put all the correct parts back on the truck to make it "better than new" again, you will think there is a HUGE difference in the value of various trucks (because of bullet #3).
5.) How much do you value your time? Some people see a truck that needs many hours of labor, but only a few inexpensive parts, as a "cheap fix". Others, with less time or who place a higher monetary value on their time, see all that labor as a "giant expense". Nothing wrong with either one, but these people will never see eye to eye on value.
6.) These are hugely expensive trucks, when the military buys them. We are buying them all, even at $25k or $50k, at pennies on the dollar. You're getting more capability than anything even close to this price range. So in a big picture sense, yes, they are all worth practically any price they sell for.
7.) Because of #6, parts for these trucks are all "parts for $100,000+ trucks". So the takeaway is that fixes can be very expensive, easily more than you bought the truck for (at whatever price). You might have paid $10,000, but a new alternator is $1500. A quality, rebuilt engine on the commercial market can easily be $10k. So a truck that is less risky (because it's in better repair, has been through depot recently, has been owned and nursed back to health by a military vehicle enthusiast, etc.), could be saving you tons of money, even if you pay tons more for it.
8.) There are outlier stories for everything. You'll always get a guy who says "I bought mine at auction for $500 and they said it didn't run... I changed the fuses and now I've put 100k miles on it.", but that doesn't mean you should pay attention to that story. You similarly shouldn't pay attention to the other edge case, where a guy paid top dollar and it caught fire on the way home. Look for the trends, in how people use them, how many repairs they do, etc. to understand the real Total Cost of Ownership.
9.) Personally, I avoid the lowest and highest mileage trucks, and look for the middle ground. I don't want a truck that just sat for 20 years. I want one that was driven little bits frequently, so that it made it into the motor pool more, people had more chances to report issues, turn things over to get some oil splashed on the seals, etc. I don't want one that was driven to **** and back though. Middle ground on these trucks seems to be around 15-25k miles, meaning it saw an average of about 75-100 miles per month across its life.
10.) Nobody wants to pay more than they have to for something, but if you would agree that something like +/- 10% couldn't justifiably be called being "taken" on the price, then you have at least a few thousand dollar spread that's not even a big deal.
11.) Location is important, because shipping is expensive. I paid $3000 to ship mine 1/2 way across the country, so it would be twice that coast-to-coast. Add that to #10 and you could see several thousand dollar differences in price. Also, a seller who bought one and shipped it to themselves is going to try to recoup their shipping costs in their sale price. This shouldn't be understated, since shipping could mean as much 40% extra to the purchase price!
12.) I think regular private owners generally see the LMTVs as more valuable, or desirable at least. These are huge, impractical trucks unless you have unusually large needs, and the LMTV is more reasonable than the MTV. An LMTV is just a little longer than a full-size extended-cab pickup, with a fairly comparable turning radius. The MTV adds just enough that it becomes impractically difficult to park in a normal parking lot aisle, turns just wide enough that it requires more special attention, requires a CDL, requires more expensive license plates in some areas, etc. People who are desensitized to these differences, because they own other military vehicles or heavy equipment, may see the MTV as the more desirable truck because of capabilities, but that probably isn't true of newbies.
13.) Instead of thinking of the question as "Is this price good?", I would phrase it as "In the price range of $7500-25000 that we know these sell for, does the quality of the truck justify roughly where in the range the asking price is?". That's a more objective question that is easier to answer, with less opinions involved.
