They provide a service to their users by offering debt that might be at a rate slower than would otherwise be available to them through other lenders.
Do you have a passion for teaching and want a way to get paid to do it passively? Then, creating an online course is a great way to make money while you still have a full-time job.
Suppose you enjoy writing and have a passion for a subject. Then, starting a blog could be a great option for you. Typical ways of monetizing a blog are through ads and affiliate links.
Currently the most out-there idea on this list. Did you know you can buy an 18 wheeler, get a driver, and lease it on to one of the large carriers?