Since it's getting chilly out, walking or running outside may seem less and less appealing. You can buy an expensive motorized treadmill or spend lots of money on a gym membership, but if you want a cheaper or greener option, a manual treadmill may be just the thing you're looking for.
These treadmills have no motor and use no electricity. All it takes is your muscle power to get the belt moving, which means it's good for your body and the environment. Not only that, but it makes much less noise so you can listen to music or watch TV and be able to hear without having to wear headphones.
This one is called the TrimWalk Folding Manual Treadmill ($100). Just like when you walk or run outside, you can set the pace yourself. It has a display that will tell you your distance, speed, time, and calories burned (powered by a AA battery). You can also fold this up and put it under your bed when you're not using it. This is a great option if you're looking for an inexpensive treadmill.