I agree with Tom...it's really up to you to decide the value.
Now, that said, if you were thinking of just tossing it, and going to buy a replacement...here is what I would do...
1.) Price out a replacement lens. (Amazon, E-bay, etc....but an equal lens)
2.) Price out what it would cost to have this one fixed. (include shipping, etc.)
3.) If it's cheaper to just replace it, THEN, I'd try to take it apart, and see if I could fix it.....with the full expectations that I'd be tossing it all in the trash upon completion:S....and saved a bunch of money, if I happened to make it work:) After all, you are at the point of "who gives a sh*t!" anyway, so why not try and fix it.
Keep in mind, that even an old Nikon lens is probably a pretty valuable piece, so it may very well be worth getting it fixed. Compare new/used Nikon lenses for replacement...not just some cheapo zoom that you might find on Amazon.
My advice on disassembling the lens....take pictures of it as you go, so that you can put it back together again. That's what the guy on American Restorations does.:)
Good luck:)