Question on the proper pricing of a 1971 Grande?

Hello everyone,
I'm attempting to give an offer to my neighbor for her 1971 Grande. The poor car has been sitting in her driveway for about 4 years now. The engine of the car doesn't even kick, so it goes without saying that she won't start up. There's rust on the edges of the doors and around the bottom of the body. So I was just wondering if anyone could give me some sort of estimate of what its worth in the condition its in?

Thanks!
Justin