The Insight UTL M2 tactical light is about $200 bucks brand new, and about $125 used. That puts the gun you're buying right around $600. (Plus tax, transfer fee, shipping, FBI check, etc. Whichever may be applicable)
But before I can answer your question, you need to provide some more information. Which USP model is it? 9mm, 40SW, or 45 acp? Full size or compact? You mention 18 round mags, so I have to assume those are the jet funnel mags in 9mm? Is that correct? If so, does the gun have the jet funnel attached? That piece is normally around $100, which would bring the true cost of your gun down to $500.
If they are jet funnel mags, does it also come with the original mags? The JF mags are VERY expensive, so if they are in good shape, you could probably figure the cost of your gun is down to $475.
How "used" is it? What is the date code? How many rounds are through this gun? What is the overall condition? Any holster wear? Is the bore rifling sharp and mirror like? Do the rails look beat up? What kind of sights does it have? Original? Night sights? Adjustable target sights? Fiber optics?
Is the slide blued or stainless steel? Is the frame any strange color like OD green or gray? Does it have the original HK case and manual, spent shells, warranty card, etc?
Is this a "normal" USP or might it be a Combat Competition, Custom Combat, Expert, Tactical, or ELite? Does it have a threaded barrel? Does the trigger have an over travel screw sticking out of it. LEM triggers are awesome but they take some getting used to. Quite different than SA/DA. I personally love them, but many others never get the hang of them.
So, yes, it may very well be worth the $729 based on your answers, in fact, it could be a huge bargain -- BUT it may also be a total ripoff if the gun is in poor condition. Try to answer as many questions as possible and we'll be able to give you a better idea.
