Answer:
Wanting to buy an mp3 player but waiting until you have the cash (rather than buying on credit) is both mature and responsible
Step-by-step explanation:
When a person is going to acquire any kind of good that has an elevated cost, it is a demonstration of maturity and responsibility to better buy it in cash instead of asking for a credit since this keeps the person away from unnecessary debt that could become a problem if the person does not have the economic stability to afford the payments.