I hate to say this, but....
If you are good at scrounging and building, you can build something nice for 5 grand. If you have to do it in a three or four month period and are starting from nothing, the probability goes down.
Then, for living on the cheap, a used single-wide can sometimes be gotten and installed for that price. Complete with appliances. That work, if you're lucky. Of course, it's going to be hot in summer, cold in winter. And your neighbors, if they're not in the same boat, will dis you for trailer trash.
Do consider, though, if your housing money has to include water and waste systems, electricity--utility company (constant expense) or homebrew (one big expense, occasional biggish lumps of money thrown at it), or the drains for lights and so on that now count as minimal, but will add up rapidly if that's all you have. And air conditioning of one sort of another--heat, cool, dehumidify, ventilate, move, etc.).
Mini-hydro is the cheapest of the power systems, although the only one I know of requires constant tinkering. A mini-hydro system needs much less in the way of battery support because it runs 24 hours a day (except possibly in conditions of serious flood or drought}.
The OLD Rob Roy book on building without a mortgage can be inspirational. I haven't seen the new one.