I see enlargers on Craigslist often. I also see them on news paper classified section. I was offered one when I was shopping at a local hobby/camera store. I gave one away at a local community college. I saw a few for sale at a local art school. I bought one from a used camera store for pretty much nothing.
Because of difficulty in shipping enlargers, you are pretty much limited to your local area as a source. If you keep your eyes open and your wants known to many people, you'll likely to run into one.