Building a shack isn't that hard, see https://www.youtube.com/watch?v=P73REgj-3UE

Try building it in the forest though - it is most likely illegal due to some rentier (or government) already owning it. I think the grandparent has some truth to their words.

Existing outside the dwelling is illegal. Dwellings are owned by the elite rentier class, so you need some money just to exist (unless you are a rentier).