I'm not going to use my parent's money to make major purchases.
That's good. Was there something you wanted to buy with your parent's money?
I was thinking of buying a very expensive World of Warcraft account.
Your parent's money is not really yours to use, you are so nice to not want to use it for something expensive. Wait until you get your own money and buy what you want to.
Meh I'll buy it at a later time.
That's good, you might be able to find it cheaper later on. Your parent's will appreciate you not taking advantage of them to buy a game.