How to make a lot of money fast!?

So I am 17 and I just found out that my internship will not be running next month like I originally planned and I was suppose to get $500 out of it. School is starting soon and I need about $500 to buy two pairs of uggs and a north face fleece. I know that sounds kind of spoiled but my mom is buying my actual school clothes and I don't want her to spend all that money on 3 items. So I really need to figure out a way to raise money. I was going to sell some of my stuff on Ebay but I'm not sure how that works. And I can't babysit because all the parents with children have older children who could do that for free. So please help, and I need serious answers you guys. Thank you :)