I would use a candle for this, but that's just me.
Meditate, charge energy, focus on your goal. When you feel you've charged enough energy and can visualize you getting the MacBook [parent hands you a present, you open it and it's a MacBook] say a chant. Make it up yourself, but something like:
I have been good all year
[Your deity] know I am sincere
please reward me with one great gift
a new MacBook is my wish.
I would do this every night starting from the New moon to full moon, giving an offering on the full moon. After you're done, work towards the goal. Tell your parents you only want the MacBook, save money, do extra chores, bring enough positive energy your way.
Keep in mind you don't want to be greedy, and you shouldn't ask for a MacBook one month, an iPhone the next, an iPod after that. Think about what you ask for, in terms of cost, and then think if you really deserve it. If you feel you do, then try wishing for it, but be prepared to prove your worth for such a gift.