Budget and midpriced treadmills are sold at large retailers such as Dick's Sporting Goods, Sears, Sports Authority, and Walmart. For more expensive brands, you'll generally need to hit a specialty fitness store. Whether you want to shop online for the best price or in a store, try the machine in person first. You might notice a problem--the deck is too short for you stride, for example--that you can't detect by sight or reviews alone.
Here are other criteria to consider:
Size. Most treadmills are about 6.5 feet by 3 feet. Folding treadmills are about half the length when folded. Don't assume that because you buy a folding treadmill you'll actually fold and stow it. If that feature is important, try folding the machine before buying to see how easy it is to do and whether folding makes it easier to store. You'll also need adequate space--about two feet on each side and the back--to get on and off safely.
Safety features. All tested treadmills have a safety key that clips onto clothing and turns the machine off if you fall. People with children at home or as visitors should make sure that they can't access treadmills, and hide the safety key.
Ergonomics. If running is more your speed than walking, check treadmills' deck length, since you'll need a longer one to accommodate your stride. If you want the space-saving that a folding treadmill provides, make sure the deck isn't too heavy to lift.
High-tech features. Docks for iPods, USB ports, and wireless Internet connectivity are popping up on many treadmills.
Adjustability. Most tested treadmills incline to at least 10 percent; some go as high as 14 or 15 percent.
Assembly. A treadmill can weigh up to 400 pounds, so ask about delivery and check whether assembly is included or available at an additional cost. It might be worth it if you're not particularly good with a toolbox. It generally takes our experienced engineers about 1 to 2 hours to put together a treadmill, depending on the number of steps. Lifting heavy parts, adding applying grease, and working on your knees are part of the process. Some of the steps require two people.
Warranty. Look for one that provides two to three years of coverage on major moving parts and a year on labor. Our surveys suggest that an extended warranty probably isn't worth it.