Singing dollar, dollar bill ya'll!

Last night, while eating his dinner, my dirty faced little boy declared he was done eating after one bite. I said, "Oh, that's too bad, I was hoping you could have ice cream with me. If you'll eat your dinner all gone, you can have some ice cream!" He looked at me with the cutest sideways glance he always gives and said, "How about a dollar?"

When did ice cream stop motivating 3 year olds?