How would I convince my father to get me Xbox Live?

OK, so I have the Xbox 360. And I don't mean to be to ask a lot, but I want to get Xbox Live Gold. My dad says we're not getting it because we've already spent too much on the console. But I am only playing Zombies on Call of Duty: Black Ops by myself and I am getting bored. I want to play with my friends online, but my dad says to have the come over to our house to play. I find that obsolete considering that every console has an online community. I get straight A's, I never get in trouble, and I haven't had any write-ups (demerits) in school this year when many have had at least one. I am also tired about the fact that I must persuade him to get things. I can afford this expense, but he says that he doesn't want me to be sucked in to a capitalistic game. I understand that he means well, but I want some financial freedom, and I'm 13. What should I do?