One of the best ideas I've ever seen was this guy 2 years older than I.
After high school instead of going to college, he asked his parents if he could have the money they were going to give to him and he started his own business.
He opened a tanning bed place in a small, but growing town locally.
It was a success. He then kept that business then started his own pool, spa, & billiards store (selling & installing).
Last time I talked to him he started his own manufacturing company producting spas from raw materials.
He said he plans on selling it within 2 years and retiring.
He will be 35 yrs old and a multi-millionaire.