Show Me the Money Part 1

Eli:  Mommy I want that sword from the junk store (antique place).

Me: Um no. If you want something you are going to have to work for it, plus you will stab me and/or the dog.

Eli:  Mommy, you are good at massages.  How much money would you charge?

Me:  Say 20 minutes would equal 20 dollars?

Eli:  Well then I would make 15 dollars and you would get 5.

Me:  Why would I get 5 when I am doing all the work?

Eli:  Mommy I came up with the idea, so the person who comes up with the idea makes all the money.