Pet store puppies come from PUPPY MILLS. They are poorly bred, and are often mixed breed dogs in spite of (false) registration papers, they are nearly impossible to housebreak, they have never been inside houses, cars or yards. Frequently, they are already incubating Parvo virus when you get them (want to spend a few thousand at the vet hospital?).
Please don't buy from a puppy mill. You could get a top quality AKC dog from a highly reputable dog breeder for that price. Every puppy they sell, means that the mama dog will have to make another litter in that filthy stinking cage...while the owner gets stinking rich. Puppy mills feed the dogs the worst, cheapest food they can find, veterinary care is nonexistent, and dogs with 3 legs or 1 eye or half a tail chewed off by rats are bred. We all want to shut DOWN the puppy mills, not fill the owners' pockets with cash money.
If you don't buy that puppy, it and its mama and a whole lot of other dogs and puppies can go to rescues, get health care and love and help adjusting to life outside a cage and eventually find new homes. Every pet store puppy sold is like making a contribution to a puppy miller's bank account. Please don't do that.
You say she isn't from a puppy mill? How do you know? Did they say she was from a "trusted breeder" or a "licensed kennel"? Ha! I've heard THAT before! Puppy mill is a slang term for a commercial breeder, a person who breeds dogs for profit. Puppy millers don't call themselves puppy millers. No, they speak of their USDA licenses (inspected once a year, so the cages get cleaned once a year) and call themselves professional dog breeders.
The puppy is grotesquely over priced. I'm betting you that it is 100% from a puppy mill, and I don't care how pretty the brochure or the website looks, those things are easily faked. Pet store puppies come from puppy mills and there are puppy mills in every state. Even the Amish run puppy mills.
I bought a puppy from a puppy mill once. It died young. In spite of a long list of promises and guarantees, when my dog got ill, they did not answer one phone call, one email, one letter, one card or one registered letter from me. And when I wrote them later to say she had died and it broke my heart, they didn't even say they were sorry. They never contacted me at all. The most a puppy mill or pet store will do for you is to have you return the puppy you have in exchange for another which will probably get just as sick.
Try akc.org or the national or state breed club of the breed you like. Go to the Canine Health Information Center website and see which tests *should have* been done to both of the dog's parents before they were bred.
Pet store puppies almost always come with a health certificate. This means that a veterinarian, whose job it is to look at hundreds of puppies a day, scrawls a signature on a piece of paper saying that the puppy *appeared* to be okay at the time it was looked at. This has to be done to legally ship puppies to other states, so please don't think it means anything other than the fact that the pup came form a puppy mill.
Ask the pet store to show you the pedigree and registration form. Probably no "Ch." on the whole pedigree and that means t wasn't bred to the breed standard. Jot down the breeder's address and phone number. Give him or her a call and ask about the health screening. Oh, never mind, the pet store won't let you see those things until AFTER you have paid for the puppy.