Mom is preparing dinner, and Dad is reading a book.
Shanshan: dad, do you want to look at mom?
Dad: sure.
Shanshan: if you look at mom, you have to pay me.
Mom and Dad can't stop laughing.
Dad: how much?
Shanshan: you have to pay 10.

For 4 year-old girl, 10 means a lot even without unit :) :)