If you love shopping and have a great eye for deals, you can become an eBay or Amazon flipper! Scour garage sales, estate sales, or thrift shops for good finds. If you are lucky, you can head straight to eBay or Amazon and sell it at a mark-up.
If you have any experience teaching or are currently homeschooling your kids, you can sell your materials on Teachers Pay Teachers. Other teachers and homeschooling parents will pay for good, quality printables, activities, and even full lesson plans.