What is the minimum amount you can have on a debit card?

i'm 14 and my parents are thinking about getting me one but is there a certain amount you have to have on there? Like a minimum amount? And what's the youngest age you can get one? Don't say i don't ned one because that's my parent's decision to make and your opinion doesn't count. Thanks? Btw i don't mean to be rude but i'm sick of people's unnecessary opinions, also if you end up putting your unnecessary opinion anyways then you have no life. :D HAVE A GOOD DAY!!!!!!