Describe a little better how it runs. When you get it started, does it rev right up if in neutral ok? When you drive it and not use the hydrauics, does it pick up speed and travel ok? Does the motor seem to be skipping? When you have trouble starting it does the starter spin away and the motor is turning normally but it won't start? The prices for parts seem about right but first it would be nice to see if you need them. Why a starter, does it turn ok while trying to start? If it is skipping, a compression test would be in order. Also a voltage test on the battery while running would be good too.