A restoration can be a little or a lot. It all depends how much you want to get in to it. Paint, thinner, hardener, and accessories will run between 1 and 2 hundred(or more) Degreaser,Sand paper, body filler maybe, paint stripper, maybe sandblasting??? the list could be endless. Plus, there may be parts you want to replace. The biggest thing you will be putting in to it is time. A lot depends on the tractors' condition. You could do an awful lot for 500 bucks........start with cleaning it up. Dont forget, this could also be done a little bit at a time, as money permits. Bottom line is have fun with it! The tractor has family history so you will always be glad you worked on it regardless of how much you do.
           I hope you decide to go for it!
                      Cal