You've decided to start exercising and decided that using a treadmill is the best way to go, but you can't fit an expensive treadmill in your budget so you decided to go with one of the cheap treadmills. Although you can find some good quality cheap treadmills they will not be the same quality as the higher priced treadmills.
The only good reason for considering cheap treadmills is that you might not know exactly how dedicated you will remain to your workouts. The idea of spending two or three thousand on a commercial quality machine which you may get tired of in a couple of months does not make much sense.
If you've only invested five hundred in a machine, on the other hand, you won't feel as foolish if you decide treadmill workouts aren't for you. Buying a more expensive machine, however, may give you the incentive you need to stick with the program!
The belt should be of good quality. You don't want the belt to slip or stick while you're walking or running on your treadmill or worse fall apart altogether.
Make sure that the controls on your treadmill are easy to use and understand. If you're running or walking at a certain pace and you get tired and want to slow the pace down you don't want to have to try to figure out how to do that or you try to do it and the machine doesn't respond, that can be very dangerous.
Most of all whether it's on cheap treadmills or expensive treadmills you don't want to over do your exercise routine. Be aware of your heart rate and check with your doctor to make see what is safe for you to do.