I just found the Kelley Blue Book website this morning (www.kbb.com). The 
Kelley Blue Book is commonly used by car dealers, along with the NADA 
yellow book. Maybe you already know about this site, but if not, I found it 
to be a really neat site for looking up the retail and trade-in values of a 
VW.  I found it far more complete and accurate than the Edmunds site, at 
least for busses and Vanagons.  For one thing, it adjusts for regional 
price differences (you must enter the State you live in), which can be 
substantial, as we have seen on this list.  But what really impressed me 
was that it is clearly customized for the Volkswagen van itself, rather 
than just adding generic values for different options like the Edmunds site 
does. (You get the feeling they researched it a bit more carefully.)  For 
example, I tried looking up a '77 Westy, and it actually asked me to 
specify whether it had the optional stove, fridge, side tent(!), etc.  Sure 
enough, it quoted different values if I typed in different options (or 
different states in the country).  You have to read the FAQ's, however, to 
discover that the "trade-in" prices quoted on the website are actually 
lower than the wholesale prices listed in the Kelley Blue Books they sell 
to dealers. Also, I didn't always agree with their prices based on what 
I've seen locally (I thought their later-model values were a bit high, and 
their earlier-model ones a bit low), but that's just my opinion.  In any 
event, it seems to be the best used car valuation site on the net.

For what it's worth (no pun intended), I looked up the value of the '89 
Westy I'm asking $12,500 for. With its specific options and mileage, the 
Blue Book retail price for it is $16,000. (Dealer trade-in is about $10k, 
so it seems I'm actually asking closer to wholesale than to retail.)

-Ron Salmon