Whether for high school students or adults, you can monetize your expertise by teaching people with less experience or knowledge than you in that subject area. You can work with an established group like Kaplan for, say, SAT tutoring, or you could try hanging out your own shingle and making your services known either to students, parents and schools in your community. If you are targeting adults, you can create your own website or list your services with adult tutoring companies.
There is a demand for finding reliable home improvement contractors, and this is a business opportunity you can address. You can start a home-based contractor referral service that connects homeowners with prescreened, reliable home improvement professionals like painters, plumbers, carpenters, and electricians. Contractors will then pay you a prenegotiated commission on work secured, and you can keep your service free for the homeowners.
Diligence. In this industry, the line between scams and honest businesses is blurry, so you need to do your homework before accepting a position. Call the Better Business Bureau in your area to find out if there have been any complaints filed against the company, and do an online search on their name. Alpine Access is a well-respected company in the field, and Call Center Careers is a great place to look for legitimate call centers looking to hire.
Please note that some of the links below are affiliate links and at no additional cost to you, I will earn a commission. Know that I only recommend tools and learning resources I've personally used and believe are genuinely helpful, not because of the small commissions I make if you decide to purchase them. Most of all, I would never advocate for buying something that you can't afford or that you're not yet ready to implement.