If you want to drop off the grid, there are certain things that you would have to sacrifice. You have to give up your current way of life and adapt to a new one. You have to give up your job, your car, your house and your money to fall off the face of the earth.
So how would you live on practically nothing? A good place to start is to find a new place where natural resources are abundant. If you have watched the movie "Castaway" the main character lived for almost a year on just fish. If you make a shelter out in the woods, be sure to make it near a river or waterfall. Not only is it a great source of fresh water, you can also find meat because of all the fresh water fish living there. You can also find wild game near these rivers because all of them need to drink water, so they will come and drink from the rivers.
If you want to build a shelter, you can also make use of the natural resources around you. Or if you want to finish off the remainder of your money, buy a little wooden house in the wilderness and stock it with supplies you would need. You can afford not to finish these supplies quickly if you know how to take advantage of the natural resources surrounding you. You can also opt to sell the things from your past life. Sell your car for cash, or sell your expensive electronic equipment such as televisions, cameras, cellular phones, video game consoles and the like. Take only the clothes you would be comfortable with and sell your more expensive ones much cheaper for straight up cash. Remember, you are basically living off nothing so you would need all the extra cash you can get, from even the smallest items.
If you are living near the beach, make sure that whatever shelter you have is not directly under the sun and is sturdy enough to withstand the strong winds and possible storms. Beaches are also full of natural resources you can use to live. The water is full of fish to eat, and there should be a river opening up to the ocean; here you can get fresh water and also, fish. There are also coconuts whose juice can be used as drinking water and the meat is also edible. The coconut shell itself can be used as a bowl or as a plate. Shave off some parts and you can use that as your spoon to scoop out your food. The coconut leaves can be used as a good roof if you are making a makeshift shelter. If you don't have the skill to make your own shelter, there are also caves dotting the shoreline that you can use as shelters. Dry driftwood makes for good fire wood at night.
When living off on practically nothing, you have to be resourceful and smart. Take advantage of what nature provides you and you won't have any problems at all.