In my campaign's core area, individuals might "own" land, but they cannot sell it. Any farmland, pasture, forest, etc. is owned in common. One only "owns" ones house. Even nobility cannot sell or buy land. Lands "owned" by a King or noble are always "owned" by that King or noble line. However, lands can be shuffled as a result of warfare, clan marriages, etc. If somebody wants "new" land, they have to take it from someone else. There is no "price" put on land other than the price of kicking its current occupants out.