I believed that the Blue song "All rise" went "1 for the money and the free rides, 2 for the lager cheques - denied!" (it's actually "2 for the lie that you denied")
I thought it was about someone trying to buy beer with a cheque, but it was rejected.
A childhood belief about misheard lyrics

others believed things like this
- When I was a child, I used to know that using cheques you could spend an endless amount of money— lollo
- When I was little, I believed that banks were places where anyone could go in and take some money for free. Anon
- When I first heard Matt Monro's song "Born Free," I thought he was singing "Porn Free."Anon
- i thought an ATM machine was something which gave free money!!— Armani
- The song "Reverend Blue Jeans" turned out to be "Forever in Blue Jeans." Who would have believed that?— music lover
- I used to believe that the song "Another one bites the dust" was "Another one rides the bus"— Emmy