My Dad's Vintage Tractor Collection

I have several International Harvester tractor toys by Ertyl purchased by my father in the 70's. They are still in the boxes. Though the boxes are weathered/dusty, these have never been taken out and played with. I'm trying to sell these for him. Any idea what these are worth?

1. Massey Ferguson tractor
2. International 4-Bottom Trailing Plow
3. International Turbo Tractor with Cab
4. Massey Ferguson 4-roller tandem disc
5. Massey Ferguson Planierrupe MF 300 Full Power Shift Getriebe