Prior to me turning seven, my grandmother used to give me $2 bills for hitting home runs in Termite League baseball, which I would dutifully put into the bank, then when I wanted to take out $10 for something, I was kind of disappointed that I didn't get the same $2 bills I had deposited back.
I wasn't disappointed, but was actually amazed, around that same time when I learned that when radio stations play songs, the band is not actually there in the station playing. Hearing the same song on two stations at one time clued me in on that whole recorded-music situation.