How Can A 15 Year Old Make 300 Dollars In A Day?

There’s something that I want very badly and it is $300. The sale ends in 3 days. My parents refuse to help me pay for it, even though I say that I WILL pay them back when I get the money (which I will have soon through a sale in eBay, but not in 3 days). I do not have a job, but I sell OOAK clay figurines on eBay instead. How can I make $300 in one day?