Used Treadmills? Advice

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I was sold when I saw a brand new ad on Craigslist, this morning. offering a NordicTrack Commercial ZS for $250. Wanting to be the first to make an offer, I called and made an appointment for what would've been tomorrow morning. Well, I come home from work to a new e-mail from the seller saying that someone's interested for $300, and would I still like to buy it? I get it... We all want the most for what we have, but really? I'm frustrated and upset, and now lacking a little bit in motivation. I'm starting the new year under 200 lbs, something I'm so proud of, and I thought it would be a welcome addition.

Anyone with advice for someone in the market for a used treadmill? I'm tired of weeding through ads about treadmills that are non-working, not photographed, etc. :(