Free puppies can be found at a local animal shelter. While there is usually a small fee for adoption, this fee covers vaccinations and other necessary treatments. Many shelters also have promotional days where the adoption fee is less than normal or waived.
Pet shelters take in millions of animals each year, some of which are purebred. Some rescue groups specialize in one breed, which makes it easier to find specific puppies for free. If there are no shelters or rescue groups in the area, try looking at classified ads online for free dogs. Many families offer their dog's puppies to loving homes for little or no adoption fee.