I found mine at a scrapyard in ABQ for $300 (discount auto parts, VW mostly(505) 877-6782). The oil drain plug was clean as a whistle, and when I got it home I performed a "white trash ring test" (filled the cylinders up with light weight oil, let it sit for 36 hours) I got lucky in that the rings were good, and the head was rebuildable.
I would recommend scouring the junkyards, and be patient until you find the right one to go with. The magnet in the drain plug will tell you a lot. Mine was a top-end only fuel injector fire damaged motor, which somebody gave up on.
The other approach I almost went with, was a running parts car, because that approach can be very economical. A really ugly runner can be found for $5-800.
What gave out on yours ? Good luck !