While we were in a Game Stop store, ds18, then around 12 or 13, inquired about selling back an old console. I forget which one it was. Maybe Game Cube. The clerk told him that officially GS no longer buys back that particular game but if ds was willing to sell, the clerk would personally buy it from him.
I could see ds raise his eyebrows and suddenly the wheels started turning.

It got him thinking this old system that he originally thought was "old junk," simply because it wasn't the latest & greatest, was actually valuable. He has always saved every game console and this was the first time he considered selling.
We still have an old SNES with Super Mario World that we've had since dh & I were first dating in the early 90s. It was ds18's first game ever so he still plays it now and then for the nostalgia of it.
So my long-winded point is that it couldn't hurt to ask the clerks in Game Stop if they personally know anyone looking to buy an old console. It's the gamer in them that led them to that job and chances are their friends are the same.