I answered that question in literally my first paragraph.

A free market for this would be defined as when everyone has to ability to actually own land, without anyone else in the world being able to charge additional rent on it.

So you buy land, and you own it. And no one can decide to charge you more rent for this, would be the definition of a free market.

Governments do not have this property of being a free market because they can change their mind and charge you money for it later. Therefore they are the ones who own the land and it is not a free market.

A free market would be defined as when you owe zero rent to anyone in the world, no matter if the rent is called taxes or not, and you actually own the land.