Ryan Finlay from ReCraigslist.com makes a full-time living (and supports his family of 7) buying and selling items on Craigslist. In fact, he used this business to pull himself out from $25,000 in debt and now teaches others to do the same. This is really one of the most fascinating side hustle stories I've come across because there's a Craigslist for your city that is probably teeming with "inventory" for you to run a similar business.