Dogs purchased from stores are known to have more health problems than others. There are a number of reasons for this, but the key is make sure you get your dogs from shelters or reputable breeders. If people don't buy dogs from stores then stores won't sell them - problem solved.
And for gods sake don't ever 'Save' an animal from a store by buying it. All you are doing is reinforcing that their methods are profitable and they will continue doing them.