I am interested in purchasing this truck that I found- a 1973 K5 Blazer 4x2.  
It is originally equipped  with V8-350, automatic, tilt steering, backseat, molding package, 12 bolt posi-traction, AC, and comes with extra parts plus it is unmolested (meaning no cut out for radio- truck has not been lowered etc-so its ORIGINAL) I've offered this person 5,000 but he claims that because its so rare he wants 25,000. Is  he crazy or am i just out of touch with it value and how rare it might be? Can anyone out there give me some advise or price ranges that i might be better able to judge these prices? Thanks for your help and advice.
 

Have you searched around for an average price? 25K seems steep to me...  

Have been looking 4 a few years and have only seen maybe 3 but none still in its original production state, like this one.  

But are you willing to pay that much just because it's in "Original" state???  

A lot of these vintage restoration nuts are on their own planet when it comes to how much these vehicles are worth. If your intention is to whip out the plasma-cutter and welder and hack it up to make a custom, I wouldn't waste your time with trying to find a really cherry, 100-percent original truck. Unless the guy has a professional appraisal saying it's worth that much, I probably wouldn't pay that, especially if you intend on modifying it.