A few years ago I listed numerous lots of 20 of my LPs for sale on ebay. I ended up selling a bunch to a guy in Seattle, then a local guy came over and got himself burned big time, then the Seattle guy bought a bunch more. Mr. Seattle knew what he was doing, the local guy was a moron. He picked some of the worst stuff I had, and I quoted him like 5 times more than they would ever be worth...and he bought 'em! Idiot.
Between the two of them I pocketed around $375 for maybe $200 worth of music. There was a major CD buying binge shortly thereafter, and the rest went to some legitimate need around the house...school clothes for the kid or somesuch.
I've sold a few individual LPs or CDs from time to time online, and was considering selling my extensive KISS collection when the house burned. I could have gotten around 4K out of that. Now it's ash. Oh well. Somebody else's stuff just got more valuable.