I've been reading this thread for a bit, and while I'm sure I'll get flamed out of the sky for saying this, I'm in a similar situation to you.
Firstly, you said you don't get an allowance- since you are apparently a good student and a good kid then do you think you can negotiate for that? If your parents give you incidental money for when you go out with friends, then you may need to agree that you will no longer recieve that if you get a weekly allowance (which i think is a good trade off). This will mean you can save for things/hauls, but also means you have to be aware of everywhere your money goes (which is also a good thing).
Second, could you negotiate for a flat clothing/makeup allowance every year/6 months? Then it becomes up to YOU what you spend your money on, which means you can buy MAC, but also means that if you spend all of your money on MAC then you may have to go without clothes, even clothes you need. A good, realistic budget, with time-based allocations (say, you can only spend a third of the budget each third of the time period), means you can keep clothes on your back while still buying the occasional eyeshadow. I'd do the numbers in terms of how much clothing you buy on average before you suggest this to your parents- not only so that you don't get a too small budget, but also to show that you're serious about taking control of your finances.
Thirdly (and now I'm getting preachy), don't rank makeup above books. Really, books rawk, and a well cultivated mind is worth far more than any makeup.
If you take the approach that you want to be responsible for your own finances then I think its more likely to work (hell, $5/week is a new eyeshadow every 3 weeks), but that means that you really have to take care of them- you have to be aware of where money goes and what you can and cannot afford. In the end, thats a good lesson to learn. I'm not guaranteeing that this is an approach thats going to work with your parents, but if it does then everyone benefits- your parents don't spend any more money than they do currently, you get makeup and learn the ability to budget.