They are also generally free or very cheap if you are willing to haul them away.

As i understand it though, the labor intensity of the overall build makes the earthship just as expensive, if not more so to build than conventional housing, even modern eco housing. You really only save money if you put in the thousands of hours of work yourself or with volunteers.

Ive always wanted to do it, but it's a serious commitment that may not make actual sense anymore.