1. Fiskars Momentum Reel Mower: Besides using fuel, typical lawnmowers are also huge polluters. Using a typical gasoline-powered lawnmower for an hour creates as much pollution as driving an average car 100-200 miles. Reel mowers are powered by you, not gas. This one has special features making it easier to push and better at cutting and edging. Note that reel mowers are better for yards that are already well-maintained and don't do as well at clearing overgrowth. $249.99.
2. Black and Decker Cordless Mower: This mower runs on a rechargeable battery, so it's not directly producing pollution. Unless you have renewable energy at your house, though, you'll still have an impact on the environment because of the power you're using. $459.
3. Earthwise Corded Electric Mower: Earthwise makes both corded and cordless versions of electric mowers. Besides their environmental benefits, electric mowers are also quiet and easier to start. $199.
4. Brill Razorcut Electric Mower: This is a different twist on the reel mower-- it actually has a battery to provide extra power. $429.
5. RoboMower Robotic Electric Lawn Mower: Like Roomba for your lawn, this runs on a rechargeable battery. Pricing varies by model, but these are expensive.