How can a 12/13year old make money?

Hi, I'm 12 years old and I'm turning 13 in three months and I really want to come up with $300. I have gotten into Minecraft PVP and I want an upgrade from my laptop because I have to go on optifine to mega low settings for a decent frame rate. So I want to save up for a $300 APU build. It's becoming fall right now and I want to have it all saved up by the end of winter. I know I'm able to rake leaves and shovel snow and I'm already planning on it but I need more ideas of what to do. Please leave a lot of suggestions because I'm willing to do all. Keep in mind I'm not the wealthiest so my parents can't give me allowance but if there are any ideas for what I can do to work for them, they could pay me. (Btw no, I don't want to buy a $150 50gb xbox 360, its not the same. I only like Minecraft on pc.)

Games are not god for you kid regardless i guess you can clean pools and cut yards or recycle stuff or maybe ask fro donations i don't know.

Walk down the street and pop into other peoples places, knock on the door and ask if there's any jobs you can do for a few dollars. Before long the few dollars will build up.

I'm guessing your a guy judged by mine craft, and shoveling (forgive me if I'm wrong.) I'm a 13 year old girl and I myself need extra cash. I usually babysit which actually earns tons of money. But babysitting isn't usually a guys thing so I recommend walking dogs that'll get you some money.

Ask neighbours if you can walk their dogs, wash cars, cut lawns etc. See if you can get yourself a paper round. Save every cent and nickle you can. A cent doesn't seem like a lot but it all adds up.