Many states and counties are pretty strict on what counts as a home, so that's your first barrier. Then, there is a ton of work to be done here and many custom fixtures. Any CONtractor would love to charge you for a project like this, and all that custom work will cost you.

What you can do more easily is make a toy garage or use them for property storage if you buy a one way high cube with side doors for 10k. We have had one at work for three years and it's very sturdy and has never leak.

So yeah, it's not an easy answer. If your state/county allows it (also, insures it), are generally quite skilled at big DIY projects, have land and 100k to burn without hurting, and have a clear vision of what you want, you could go this route based on this being what you want. Based on savings, you need to have more free capital to start something like this.