Could you handle composting your own toilet waste? What about doing away with the convenience of the supermarket, and growing all your own food?    Choosing a life that is more sustainable and self-sufficient is becoming easier, and more realistic for many of us, and living off the grid can also be very affordable in some parts of the world, once you get past all the up-front costs.   Ian Usher is the co-publisher of House Sitting Magazine. He also once sold his whole life on eBay, and scored a movie deal with Disney. But the chapter of his life that we’re going to dive into today is the one where he lived off the grid on his own Caribbean island, off the coast of Panama.