I taught a kid who saved up his paper route money in 7th grade to buy a lawn mower. He started mowing lawns as a summer job. By 10th grade, he had three lawn mowers and was subcontracting mowing work out to other students.
The summer after 11th grade, he had saved up money to buy an old truck, then worked bringing junk to the dump for people who didn't have one (meanwhile, his workers kept mowing lawns).
By the end of 12th grade he had bought equipment to seal and repair asphalt driveways and paint lines – equipment he tows around using his old truck.
Three years out of high school and he's getting municipal contracts to paint lines on the roadways and parking lots – work he's partially subcontracted out to others while he goes to school full time working on a business degree. He still contracts high school students to mow lawns (ETA he also has contracts to mow grass and clear brush with several municipalities in the area, as well as local businesses)
He's currently saving up to buy heavy equipment (dump trucks, loaders, backhoes, etc to further expand his business opportunities.)
I've never seen a kid with such self-motivation, drive, and determination. It's enviable!