Nothing beats teaching more novice learners about your passion, hobby, or craft as a business idea (that's a common theme here). Explore dozens of DIY portals (such as DIY.org, DIY Network, Instructables and Mahalo) to get business ideas on how to earn a healthy side income just by showing others how to do the things you love. You can also sift through the countless ad-supported YouTube channels that teach just about anything from guitar strumming to 3D printing.
Using a food delivery service can’t necessarily earn you money, but it can help you save you money if you constantly find yourself throwing out half the food you buy. Food delivery services send a box of food every week with new, sometimes unique vegetables, meat, fruit, and so on. If you don’t have time to shop and want simple meal-prep that leads to a good meal, a food subscription service may be perfect for you.