I have bought a few clocks off of CL. People tend to get stupid with the prices though. An old clock that no longer runs is not "worked a few years ago -needs a tune up" A clock that doesn't work is like a car with a blown engine. You basically have to strip it all the way down and build it back up again. Take a real clock to a repair shop and see how much it costs to "get it going again." Unless a simple dunk-n-swish cleaning gets lucky and makes it run temporarily it is often a full-on job including reaming pivots and often adding bushings. Old clocks aren't worth much unless they are C&V special but everyone who has a high-volume cheap (but old) clock thinks it is worth $100 or more.

Then there are the cuckoo clocks. A lot of clock guys won't touch them. I like working on them but they are the PITA of the clock world... Usually they aren't worth what it costs to get one running again unless you do it yourself.