For absolute lowest do-it-yourself cost (if you're handy with some fabrication work), it's pretty well established that the two contenders will be the VW inline four such as from the VW Fox or Audi 80/90 and the Subaru boxer four such as from any Subaru Legacy.  Used motors for both can be had for very low cost and both are long-lived and reliable engines.  The Subaru fits like the original WBX, is a more modern and efficient engine, and has better overall torque and driveability.
For info on the Subaru swap, the place to go is the Yahoo Subaruvanagon group.  Probably a lot of people on this list could help you with the VW inline four swap.

-Hans
East Coast Vanagon
www.vanaru.com

----- Original Message ----- 
From: "Neal Barrentine" <vwneal@BLUEMARBLE.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, March 29, 2006 8:41 AM

>        I have a 1986 GL that I want to upgrade the engine on eventually. I
> have read about several different options, including the VW turbo
> diesel, 4 cylinder from an Audi Fox, Audi V8, Zetec, etc, etc. Even if
> I had unlimited funds I still would ask for others' experience with
> various swaps, but I have very little money, average mechanical
> ability, above average enthusiasm for the beast, and I know a guy who
> hauls wrecks for a living. What, in your opinion, should I have him
> keep his eyes open for me in the way of donor-mobiles? Both for engines
> and other goodies? Thanks, fellow Vanagon afflicted!
> Neal Barrentine
> Bloomington, Indiana
> 1986 GL
> 1960 Baja Bug
>