Coin Slot Jimmy
A little community center/arcade where I used to live as a kid had an air hockey table in the back room. Somebody figured out that if you jimmy the coin slot in just the right way, you could get an extra three or four games out of one quarter until the thing was fully pressed in and you’d have to put in a new one.
None of us had much money, so this was a lifesaver. The employees didn’t really care because what money we did have was typically spent at the snack bar, so they made money off us anyway. I kind of miss that place. They always had fresh watermelon for free for kids who had absolutely no money so nobody would feel left out.