What are some ways for a 12 year-old kid to make extra cash?

Okay so my birthday is coming up in June and I can't get a PS3 unless I have the money. I need need $300 more dollars to get it and I only make $10 dollars a week and I have over $400 dollars saved up. I don't want the new models. I want the older 80g motorstorm bundle, but it costs $755 dollars. My mom says I can't get if I don't have the money and I don't think she'll give me some extra cash or raise my allowance. If you cann't think of any ways for me to make more cash then can you tell me where to get a cheaper one or give me a link to a website that sells that kind. And I don't want a used or refurbished one because I like mine brand new and my mom won't let me shop from ebay.