Max, no trouble...
The reason they say what they do about pricing posts is that it varies too much.
What might bring $200 in Texas may bring $800 in Washington.
Then there is the plethora of different scenarios that cause prices to change too...condition, options, etc, and all that coupled with a local market price difference means there is NO way any of us can accurately tell what the "going rate" for something is.
In reality, the "going rate" is whatever you are willing to pay for a tractor in its current state.
If you would like to get a VERY rough idea, see what they sell for on eBay, or Craigslist, or other equipment sale sites...then sort out the ones in your area, and you will have a rough guess as to what to expect.
Keep in mind though, just because your neighbor got a nice working 120 for $350 doesnt mean you can talk the guy down thats asking $800 for one in the same condition...because these are rare tractors, and its not like you can just go right down the street and find another one for sale.