Pet stores are tempting. I got Chewy at one. I knew nothing of puppy mills at the time. So far he has been very healthy. To my surprise he is only 5.2 pounds... the store thought he would be bigger. He cost a lot... we don't have cheap pet stores here... you pay as much or more then a breeder. Again I knew NOTHING!!!
Pet stores are not good places to go to get your puppy but not all puppies are sick that come from them. It breaks my heart to think where he came from. We got our little girl pup from a breeder. We love them both the same.
Good luck getting your baby, i'm sure the right one will come along.