My undergrad schooling was in economics and I've always been fascinated by the concepts of "fairness" and "fair market value (FMV)." To me, a "fair" transaction happens when a buyer is happy to pay what a seller is willing to accept at that particular point in time. Wikipedia's definition of FMV, which I think is a good one, is "an estimate of the market value of a property, based on what a knowledgeable, willing, and unpressured buyer would probably pay to a knowledgeable, willing, and unpressured seller in the market." Note the terms; 'knowledgeable' and 'unpressured.' Those attributes are different at any particular point in time too. On top of everything are external influences, e.g., the impact on used guitar prices by the Great Recession a couple years back and the slow recovery of those prices since. Another external influence is convenience...it's a lot easier to sell a guitar to a dealer than to try EBay or Craig's List...sorta like selling a car or a house on your own vs. a dealership or realtor.

In any case, there may be little difference between 'taking advantage' and getting 'a great deal' other than perspective, i.e., which side of the transaction you're on.

Anyhoo...given the poor reputation of Fender guitars manufactured from the mid-60's to the early 80's I'm also fascinated by the apparent collectors' prices of 70's Fenders that axe2 says he finds on EBay. But collectors' price gets into a whole different concept of "intrinsic value." :D