value of parts
without a full inventory and an assessment as to the condition of parts anything is really a guess. like others have said, buying as a whole lot/package and the physical size and weight of the general pain in the assedness of dealing with big chonky parts has a lot going for the buyer in this instance.
i'd pull some comps from the classifieds here and put it to paper and see what the back of the barroom napkin math pencils out to and then make adjustments from there.