I've seen worse Gonna need new floor boards for sure. If your capable of doing work yourself they are actually fairly reasonable in price. Prob $300 or so for the full set. The one "frame rail" looked like it might have had some cancer but it's hard to tell from the pics. Check the front shock towers and mounts. Thats a huge problem spot for those cars. If you get it it may need to be "stretched" back apart and definatly put in a brace. Got anymore pics of the car?
Does the rear squat a little? Looks like the leaf springs in the back lay really flat? Also looks like there may be a little leak at the rear differential. If that doesn't get the price to 3800 tell the gas cap is crooked, that should be a $300 discount right?