Mechanical Turk: Amazon's Mechanical Turk is a resource for doing human-intelligence tasks, or as the site commonly refers to them, HITs. You get paid a very small fee for any given HIT and you'll need a good deal of volume to make a substantial amount of money. But it is a resource you can use in your spare time to generate a small income online.
Another option that isn’t quite cash back but is along the same lines of “make money by saving money” — the Honey Chrome extension. Whenever you head to your cart to check out, Honey searches for online coupon codes or better deals from different retailers. That means no more wasted time Googling “[insert store name] coupon code” just to come up empty-handed. Honey does all the legwork for you!
TaskRabbit. Are you willing to get your hands dirty? (Nothing shifty … we're talking, like, weeding somebody's garden.) People come to this site to find those willing to do various tasks for them, such as putting together a bookcase or running an errand for them. Do as many tasks as you want, and this could become quite the part-time (or full-time) job.
Consider selling in lots. A lot is a collection of similar items that is sold in a group. For example, if you have a collection of books, magazines or similar pieces of jewelry, consider selling them all at once in a lot. You many not make as much money as you would have if you sold each item separately. However, the items will likely sell more quickly in a lot than they would individually.
Here’s a good example of how lead sales can work in real life: My second website, Life Insurance by Jeff, brings in a ton of traffic from people who are searching the web to find answers to life insurance questions. While I used to have the website set up so I could sell these people life insurance myself, it was a lot of work to process all the different requests and clients. As a result, I started selling the leads I gathered instead.