Oh the ways to get free games as a kid...
Back in the day, one of the largest theme parks in the US used tokens for their games. The tokens were very similar to nickels. If you flicked a nickel quickly into the coin mech, it'd pass as a token.
A local bowling alley has a checkpoint that was missing the door on the coin return. A penny could be flicked up into the coin mech and it'd give you credits.
Of course, I never did any of the above! Ha. Kids will do much that we don't do as adults. For example, I bought a shower curtain rod at Home Depot last week and it rang up for 1 penny at the self checkout. I called over the attendant to make sure it was right (she called the manager, and they stuck to the 1 cent price).
I taught my oldest boy (7 years old) how to check coin return slots for abandoned change. He does that now anytime he sees a game. Funny part is, he rarely plays the machines at my house. Hoping that changes as he gets older. I guess Nintendo holds his interest better at this stage in his life.