We were at this house, where the wife was selling all the games for a moving sale, while the husband was angrily mowing the lawn.
I had previously bragged to my buddy that I never pay more than $150 for anything (btw, still true, haven't paid more than that since 2005). Buddy came to look at Dig Dug, monitor decided to not come up, with my help the price instantly dropped from $300 to $100. It was now my turn and there was a Donkey Kong Junior that didn't already have someone clinging onto it. Nice, working, no sideart, a bunch of political bumper stickers on the side. We got to $175, I pushed hard for $150 to keep my street cred, she called her husband and the price went up to $500.
I was once at an auction looking for a Berzerk cabinet. Was hanging out with 2 guys, who were not real friends, but were at least acquaintances that I knew pretty well. Almost everything was going for cheap, let them know I wanted the Berzerk cabinet, most of the games were going $25 to $50 at this point. My cabinet comes up, guy one bids on it because he wants the board, and guy two starts bidding because it would be an easy multicade conversion. Ends up selling for $125 to multicade guy, whose SUV can only hold one game. I ended up with 8 games on the truck having spend about $50 overall (I flipped a CPS2 fighter in the parking lot for a lot more than I paid).