You can learn about local competitions at the public library and at the guidance office at your local high school. Your scholarship hunt shouldn't end when you leave high school. Plenty of college scholarships are targeted toward upperclassmen and graduate students. No matter where you are along the educational path there's scholarship money out there for you. And if you don't manage to land a lot of free money from scholarships, you can always earn money on your own with a job.
Some students work their way through school.
They go to school when they can afford the tuition. When they can't, they take the semester off and bump up the hours at their off-campus jobs. It may take them five or six years to graduate but when they do, they'll be completely in the black. Other students work summer jobs or part-time jobs during the school year. Some students take on work-study jobs as part of their financial aid packages.