If you ever go through Living with the Land at Disney, you have heard about Aquaponics! The Back to the Roots Water Garden in the Amazon Daily Deals is a perfect example.

On the bottom it is a fish tank. On the top you can grow herbs and other small plants. The fish poop feeds the plants and the plants filter the water. Brilliant!! It's on sale today only for $42.99 plus free shipping, and that is the cheapest I have ever seen it.