Cheap Treadmills

does any body know where to buy used treadmills in dallas and surrounding areas?

Have you tried the garage sales? There you will get cheap ones. Also craiglist dallas is an excellent place!
Try Goodwill and other resale shops!
In addition to craigslist as another had suggested, there are many used sporting goods stores in the metroplex. The best known reseller is Play it Again Sports which has many locations around the metroplex and almost always have a good selection of used treadmills and other exercise equipment. http://www.playitagainsports.com has a store locator so you can find the location nearest you.