The important/funny thing about windvane self-steering gears is folks either get it or they don't... Sort of a love/hate thing. Which, as things go, happens to be a good thing where outfitting a cruising boat on a frugal budget is concerned.
First off, the cost of most manufactured self-steering gears are silly expensive with a lot of gears floating in the $5-6K zone which is simply not going to work on a VolksCruiser budget. Lucky for us, since you can always find a just-as-good manufactured gear for less than $1k, the price of new gears really is not all that problematic. For instance, the old dependable Aires can often be found for about $600 (I've seen some sad neglected fixeruppers for $300) or so and it will steer a course just as well as one of the $5-6K windvanes. That said, I find the Aires a tad heavy/clunky for the sort of boat that a lot of VolksCruiserish folks are going to be sailing but over the years there were quite a few lighter vanes that pop up on the used market regularly (Hasler and Navik spring to mind) so with a little time you'll be able to find the right gear for your boat,
Then again, you can build one yourself for around $300 (no rocket science in sight and there is a great page with all you need to know to build any number of windvane types over at Fay Marine. You should also check out Eric's (from SV Sarana) masterly work on windvane and trim tab design which is really a must have for anyone building their own vane (best $5 I ever spent).
Oh, by the way... I happen to have a surplus to requirements, complete, late model stainless Navik windvane I just refurbished if anyone's interested...