if you can rebuild it, you might start there, replace the starter drive, and the bushing. Check it all out. If you have never rebuilt a starter or dont know what you are doing, just pick up a starter from a salvage yard, or a new or reman starter. Most salvage yard starters, even when they do go bad, are just simple solenoid replacements, which is an easy fix.
Rebuilding a starter is pretty easy though. If you dont know how to do it, find a graphical walkthrough or some kinda instructions that you can understand clearly. Once you get the hang of doing it, you can easily save yourself around 100-200 bucks or so every time you need to replace a starter in the future.
or go to rockauto, and order a starter. You can get a new one for $90+shipping.