I have one and love it despite its problems!!! I would also agree that $500 is a good price, but not anything more. The 4 cylinder diesel and manual transmission combo makes for a vehicle that will last almost forever if taken care of. As Bill stated, the run-on will be vacuum related. Seems the most likely source of trouble will be the hose that leads to the driver door.

Looks to me like the vast majority of the cars issues are cosmetic.