A flea market for electronics enthusiasts: all manner of junk for sale, from vacuum tubes to DOS mailing-list programs. It's generally a good idea to get there before dawn, as the Really Good Stuff disappears early.
At the July swap meet, I picked up a perfectly good laptop computer for $300. Sure, it's 3 years old and useless for running the latest M$ bloatware, but it runs FreeBSD just fine!