I agree. $600 is a bargain. Maybe even offer him $500 cash in hand and see what happens. Pull the spark plugs and spray Kroil in the cylinders. After a couple of weeks, start turning the crank by hand and see what happens. If it turns into too much, start tearing her down and selling parts. Rear wheels/tires $200, Transmission $200, Front wheels/tires $100, sheet metal $200, with lots of other stuff to mention, looks like you could easily make out on the deal.