You can get the reciever/dryer for the 83.5-85 Vanagons at NAPA for $30.
This is the cheapest you will get it anywhere and these work well (I have
used them before with no problem).  I would also talk to your A/C tech about
putting Freeze-12 into your Vanagon instead of R-134a as it is low priced
($7-8 a can) and works alot better.
Have fun and stay cool.
Ken Wilford (I am aware that Freeze-12 is 80% R-134a.  It's that other 20%
that makes it work the way it should!)
Van-Again
John 3:16