It is responsible to use your own money for something.
Billy is at the store when he sees a video game he's wanted for a while.
Billy wants to get a video game.
Billy saves up for the game and gets it in a few weeks.
Billy harangues his mother constantly to buy the game for him.
Billy is viewed as a responsible person and gets a generous allowance for his work.
Billy's mother sees him as irresponsible and won't give him an allowance.