so what engine parts is it missing?
an engine rebuild can cost from $1500-$4000. depending on what is required, that Assumes you have a good head, crankcase halves, crank and connecting rods, you may as well anticipate buying a new camshaft and all the bits that go with it...
then cosmetics and forks and brakes, wheels, wiring and electrics will also add more cost.
just so you get an idea of the magnitude and effort; the 73 basketcase i rebuilt cost $11,000CDN all in to get it running.
update your profile with a location and you may find some participant on here who is local to you, who would be willing to assist you...