Pricing is hard when there's not very many to choose from. You pay for what they sell for on the day.
They range in price for a chassis for CDN$10,000 (
https://www.forestech.ca/product/mor...p-tank-drill/0), up to 50,000 Euro. It all depends on how complete or restored you want it, and how close to home if shipping is going to add to the cost. And, of course, if you happen to have the money in the bank when someone decides to sell.