...I learned from the Hobans' Frances books.
"How much allowance does Gloria [the new baby] get?"
"She is too little to have an allowance. Only big girls like you get an allowance. Isn't it nice to be a big sister?"
"May I have a penny to go along with my nickel, now that I am a big sister?"
"Yes," said Father. "Now your allowance will be six cents a week because you are a big sister."
"Thank you," said Frances. "I know a girl who gets seventeen cents a week. She gets three nickels and two pennies."
"Well," said Father, "it's time for bed now."
-- From A Baby Sister for Frances (1976)
(Mother is in the other room, giggling.)