when i was 13 i started working at a retirement home. i worked there and the seniors there paid me good money, 10$ an hour, higher than the minimum wage of 7$. by the end of the week i had 100 dollars for 2 hours of work for 5 days. in fact i still work there, and since its a job off the books i dont have to pay taxes so i keep every cent, but most of that money i use to buy groceries for my brothers and sisters and my parents
sell coke (the soda), buy in bulk and sell for 50 cents $1, if you do good expand to other sodas and bring friends in as business partners, alternitively depending on the your targeted demographic, selling gum and candy work well. halloween candy is great capital for starting this kind of business. i did this in middle school and made $25-$50 a week once i got started. right after halloween in 7th grade i made $60 a week for a couple of weeks, with the right reputation u can continue selling and expanding all through high school. make sure u have the right price for the right product and keep track of profits/investments/debt etc.
With spring coming, you can make some bucks prepping/turning flower & garden beds, planting flower bulbs, raking, weeding, etc. It's almost that time. You can even buy inexpensive, pretty tulip, daffodil & crocus bulbs & make money planting them for people. It's an easy & an unusual idea for a young person. A door-to-door flower bloomer.)
When I was 12 or13 my buddies from the neighbor hood and I went knocking door to door offering to do odd jobs for cash. (only to the houses we or our parent's knew) One guy paid us a few bucks to pull weeds, another had us wash his car, even gave us all his stuff to do it with. Some people might even let you use their mower to cut their grass or whatever.
To make money, Then first to open home tutorial for Childs. When you make money make a savings account and deposit all your money, then you can increase your money by the bank interest. You need to start learning about how to manage your money and how to no use money.