Reliable sites I can buy the Aussie Fitness Pro used

I'm looking for a reliable site where I can purchase the Aussie Fitness Pro used.

I see it's retail price is about $3.4k+

I don't mind saving up for rest since I believe it's worth it, but getting it second hand for cheaper would be far more economical.

I'm not entirely settled on ONLY the Aussie Fitness Pro. I don't mind looking at other treadmills, however, it MUST be curved and manual. I can't store anymore broken useless treadmills in my garage!