I need a treadmill

I was reading something a little while ago that encourages walking as a stress reliever for caregivers, however... before a caregiver can get out and walk, they have to get someone to hang out with their care recipient. That's not exactly easy, so I have decided that what I need is a good treadmill. I had one, and I used it all the time, but then the thing had some kind of materials defect occur and the tube where the tension deal connects cracked, resulting in the tension adjustment thing sinking into the tube deal. Not sure how to explain, but, basically it gets down to the treadmill will go for two steps, then the belt is all the way to the right. I force it back to place, try to get the tension to work right again, and it goes two steps and is back to the right and jammed all over again. Can not walk on something that is doing that, so I have decided that I need to get me a new treadmill when I can. Preferably a motorized type one so I don't have to fight it like I do this one.