I have friends who live for free on a small organic farm. They do chores around the farm in lieu of rent. I was offered a small home where I could live for free last year in exchange for keeping an eye on the place and maintaining the home. The landowner lives elsewhere and wanted someone to stay there to discourage breakins (it's not a dangerous area by any means, just very, very rural and in a county where the local population has sticky fingers) . Unfortunately, it was too far from work to make sense for me.
Anyway, perhaps you could find a situation like that if you're lucky and have the right connections.