There are many individuals who buy animals cheap/steal them from yards, or find stray or lost dogs and other animals and then they turn around and flip them for profit. These individuals should be stopped from doing so. This should be against the law, and it should be very closely monitored by law enforcement and other groups such as the Humane Society and County Dog Wardens. 

Pet flipping is the practice of stealing a pet (usually a cat or a dog) from its owner and then selling it via a service such as Craigslist. Flippers make a profit by taking something they obtained for free -- through theft -- and then selling the animal.