You will definitely want a motorized treadmill. Also, unless you're training to be an olympic sprinter you probably won't need to go faster than 7 or 8 mph. Generally speaking, you get what you pay for in treadmills - you can get a fine but no-frills machine new for around $350, or you can get one with everything and the kitchen sink for up to $2500.
Minimally you will want a machine with a digital speedometer and elapsed time readout. A
heart rate monitor is also nice, but I've had a few that were problematic and didn't quite last as long as the rest of the machine. Also, pay attention to the drive motor / controller warranty even on a used machine as that will give you a relative gauge of the quality. Most have 1 year warranties, but the better machines will have 2, 3 or 5 years.
Another suggestion that I eluded to is to look for a used machine, since fitness is one of those fads that most ppl grow tired of quickly. I've picked up barely used $800 treadmills for as little as $100 when my luck has been good. Ideally February - June are the best times of the year to get relatively new machines from new-year resolutionists falling off the wagon.
Be aware that a heavily used treadmill will often need the deck / belt oiled, and often will have other problems so I would steer clear of anything that looks like it's actually been used.
). I also have no idea about treadmills but I think you'd want one that goes faster than that (if they exist ... like I said I got nothin' 
).
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Linear Mode
