Service business is the cheapest to start so list your skills and abilities.
Do you know how to do anything special, better than most people? Are you a strong healthy young man who can do hard labor? Do you own any equipment already like a truck and trailer?
Who would you like to serve and how will you sell your services? Look at landscaping, gutter cleaning, window washing, junk hauling, brush clearing, handyman services, painting, interior and exterior, auto repair, rototilling, snow removal, leaf removal, sidewalk and patio repair or replace. What matches your abilities and equipment, can you sell it?