I worked for a popular national pet store chain. We told our customers that we got our puppies from 'reputable breeders and not puppy mills'. We got them from puppy mills, and I can't express how many came in on the back of a large, pitch dark freight truck, malnourished, scared and sick.
We also adopted the cute kittens from the local sheltered and charged customers outrageous amounts of money. Most of whom just felt bad for the kittens.
Don't support national chain pet stores that sale puppies that do not come from local shelters folks.