While not completely off grid, the tiny house offers a fantastic alternative to affordable living. ---Most of these materials can be found for free or cheaper at yard sales, craigslists, dump yards, etc.
large, spacious, and undercover outdoor areas, another shipping container home this provides less natural light but would make a cheap, easily constructed farm house. With plenty of storage for equipment and ample living spaces .
Container House - get or make some cracker / biscuit / cookie boxes and play with them. Think outside the container, use open spaces that you could SIPs, or metal stud or other sustainable materials. Don't forget to think of solar, water and wind.