Why don't you just adopt a dog? It's free and you will provide shelter for a dog who has no owner. That's where I got my dog from and he's been my best bud ever since
The best places to get a free dog would be your friends. Many of my friends when they have puppies would not know what to do with them.
Ask around.
The next best thing would be dog shelters... there could be one in your local area. Most of these dog shelters would really appreciate having some of these dogs taken care of outside their facilities and be given to their forever homes.
I just did this last year when my sister is craving to have our own puppy. And my friend welcomed me when I was able to talk to him, because i don't have ample time to visit the animal shelters and I am sure I can't adopt dog there for free because of some certificates and ownership that needs to be processed and needs to be paid too. And this is going to get you free dog if you have a lot of friends.