I ordered a 1 TB drive from Dell last week for $65 including shipping and tax. And I know for a fact that Amazon has sold that exact drive for $69.99 before but it has been a little while. So if you are patient you can definitely get a better deal, but its not terrible. Techbargains can be useful.
First off, you probably won't "need" it. Second, get the macbook pro (13 inch is fine or 15 if you are feeling inspired). I have the 15 inch model and its nice and all, but I'm not sure how good of a value it really is. And if you want to play many games, you'll need to use Bootcamp and install windows.
If your account is restricted then you will have to wait til you are 18 to promote it to an adult account. Then once it is an adult account you can download whatever. Kinda makes sense if you think about it.