Oftentimes, there are medical and temperament problems that are not solvable without considerable time and expense. Go cautiously with your eyes open, if this is the route you choose to obtain the family dog. If someone is giving away his or her dog for an acceptable reason, obtaining a dog this way can be advantageous. You have a chance to speak with the former owner, find out the dog's routine and habits, and have a chance to see the dog in a relatively nonstressful environment. However, you are relying on the fact that the former owner is not lying to you.
Most pet shops deal only in purebred puppies.
These dogs are usually purchased from puppy mills or big scale commercial breeders. They are taken from their mother and littermates too early to be developmentally sound and placed in a stressful, unsanitary environment. The results are all too often sickly puppies that are nearly impossible to housebreak and have lost all bite inhibition. Your family deserves better. The truth is, if you do it right, there is no profit on a litter of puppies.