Take it from someone who knows. If you want to live in a tiny house, you should really look into buying a used rv or camper. I got mine for less than $1,000, and you will inevitably spend way more building a tiny house from scratch, even if you use recycled materials. Look on craigslist, you can find them for cheap. And the systems (plumbing, light, etc) don’t even have to be working, because as long as the framework is there, it’s pretty easy to do repairs and modifications. It’s so much easier and cheaper, and it pretty much works the same way.