Legally, i dont think many companys can hire a 13 yr old because of child labor laws. Even to get a worker's permit i think you have to be 15. So working as a hired hand may be the only option you have, which means the yard work, babysitting, walking dogs, washing cars, etc. Maybe if you or your family have a lot of old junk, you can ask permission to hold a yard sale and keep the profit. If you live in a small town, you may be able to get a job delivering the local newspaper.
Also, a lot of people go on vacation in the summer so maybe you can advertise to maybe go to their homes and feed their pets or water their plants, etc. That may be something to look into.
i hope i helped a little.
