You didn't mention how it runs. Is ther bad oil leaks, or worn clutch, burn oil. Is the tin good, and most of all, how bad do you want it?
Everything can be fixed, but in our area, if it's a good running tractor with little in the way of repairs needed to make it a operating machine, it would go for $200-$400.
And also how bad the guy wants to sell it helps to.