Save a dog and go to the animal shelter. If you adopt, your giving that caged up animal a chance.
This is the best place to get dogs for free, you can just go walk-in to animal shelters or other organizations that are taking care of stray dogs. But for sure that is not going to be totally free. You need to have some token of appreciation and thanksgiving maybe small amount of money in able just to help them for feeding other dogs.
Animal shelter is really nice idea for this user, and for everyone else, just sometimes people are afraid to get homeless dogs because they think they are sick and so on