Is this the best publication for used instrument/amp prices? is this the ONLY publication? How good is it? Obviously, what the market will bear is the true value of used stuff. And will many times need to make small adjustments for one thing or another. Generally though, what opinions are out there on this or any other resources? Thanks very much. Moderators, didn't know where to put this. Hope this is O.K. If it needs to be moved, so be it.