Depends where. Used to live in the western part of the state near West Yellowstone (parents still have a place there), and the prices there are kind of surprising. Even ignoring the Yellowstone Club, there are a lot of multi-million dollar homes sitting on relatively small plots of land (relative to other places we lived in the midwest, not relative to SF).

The western part of the state is where most of the picturesque landscape is, and there were a lot of expensive developments in the area and on the Idaho side of the border from us too.

Eastern Montana, for sure ;)