I believed that store proprietors personally owned everything in the store, and they could decide to charge whatever prices they wanted. Therefore if some item was very expensive, the storekeeper was obviously just being mean and greedy (especially if there were a lot of the thing in stock).
I told my mother that when I grew up, I would have a store that charged very low prices for everything (like a penny for a vacuum cleaner) so that everyone could afford what they needed. That's when she explained to me how stores' inventory really works, but I still didn't quite understand.
A childhood belief about money

others believed things like this
- my mom told me that if i went inside the dresses at the clothing store, the dress would eat me...Anon
- I used to believe that every time i went in a store that the grown ups had to buy me something.— jvf
- I used to think that the clothes in the thrift store were new— Ellie
- I thought change was the store's way of saying thank you.— Madeline
- I used to think that my mom had to buy ice cubes from the store and bring them home to fill up the trays.— Shawna
- for some time I used to think that at a drug store people really sold drugs.— NEO_ryu