Tricky question. It sounds as though because you just fought, everyone is upset. Why not give your parents (and yourself) some time to cool off. When everyone has calmed down, you could try to approach them with some conditions:

If you got a job, you would:

a) maintain your grades (be specific)

b) if they don't want you to work evenings, what about during the weekends?

c) limit your work hours.

Is there anyway you could make some extra money around the house? For example, could your parents "hire" you to clean out the garage or wash the car?

Remember to keep in mind that your parents will be more responsive if you approach them calmly and with a well-thought out plan.

Good luck!