How do you know that? The gun could be in top shape and come with Galco holster plus 400 rounds of quality defensive ammo.Good gun, but he's asking too much.
I shouldn't have said "better" as that's really a personal opinion and will vary from person to person, but however the p30 was designed to eliminate the few complaints of the usp series. Blocky slide and ergonomics are what come to mind. The usp could never feel as good in hand as a p30 and I'm sure most would agree as the many refer to the p30 as the most ergonomic handgun that exist. I personally wouldn't pay that much for a used usp when the newer p30 could be had for $100 more. The holster wouldn't really increase the value just because the op might not like the feel of it when worn and it could just get thrown in a drawer somewhere and not used. However if it's quality ammo that does sweeten the deal but extra mags would even be better as those go for over $50. If the op thinks it's worth it then it is. No matter what anybody else says, a deal or no deal is always personalWell, I really don't think you could genuinely say the gun is worth more than $600-$650 used (no matter how little used, used is used). If it has tritium night sights of new-ish manufacture then maybe a smidge more. Bud's has new ones listed at $771 at the moment.
As an HK fanboy I'm a bit hesitant to say the P30 is "better" than the USP/USPc. Different to be sure but both have their strengths. A USP compact is going to be just a bit smaller than a P30. I CCW a P30S quite a bit as well as mixing in a full sized USP, too.