Bad throwout bearings only make noise when your left foot is depressing the clutch pedal.
Transmission mainshaft bearings only make noise when your foot is NOT on the clutch pedal.
Telling it like it is, and not knowing what your "skillset" is and how your shop is equipped it's tough to answer this.
If you have the knowledge and a place to work complete with the equipment to split the tractor in three sections, the cost of repairing this could be under a hundred bucks plus your time or not, depending upon exactly what's wrong.
If you have a reasonable independent shop repair this it could easily cost $800 up to a grand or two.
Dunno if a FIAT stealersip would take this on, but I'm willing to bet the cost would be double that.