So, you're thinking you would like a puppy (or kitten) and venture on down to the pet store.  Inside you see cute little bundles of fur in display cases, with their big puppy-dog eyes beseeching you to "pick me, pick me". The staff is friendly and courteous and they let you handle that little bundle. It licks you in the face, and you just know that this is the one for you.
The friendly clerk tells you it's a purebred and has champions in its background. They ask you if you require any other things for your new puppy, such as dish, leash, collar...what about some food? Everything is there in this one-stop place. And how do you want to pay? Cash, cheque, credit or debit? No problem - they take them all. Very convenient.
You make your purchase and hurry home with your new bundle of love and licks.  Seems like a match made in heaven - no hassles, no problems and you've got yourself a new "purebred" puppy with papers.
Where Do These Pups Come From?
Have ever wondered where the pet stores acquire these puppies?  Do you envision a lovely area with the mother happily whelping her litter, a loving person in attendance to help her along, the best food, access to a secure play area, veterinarian attention (if needed)?  Well, if this is what you have pictured, I'm here to shatter that illusion.  These puppies come from Puppy Mills or Backyard Breeders.  The conditions that these dogs are kept in would make you cry.  Imagine for a minute, a fetid, dirty room with cages stacked one on top of the other.  Inside these cages are female dogs, lying in their own filth, often cramped for space, and with substandard food she is trying desperately to nurse her newborn pups.  She is bred on every heat and when she can no longer produce pups, she is destroyed.  The pups are removed from their mother when they are just barely weaned and taken by the truckloads to pet stores.  Some pups cannot survive the trip in the trucks and die along the way.  The survivors are then put on display in pet stores and offered for sale to anyone who has the money to purchase them, regardless of whether that person would be a suitable owner.  If, after the purchase, the pup(s) do not quite fit into the purchaser's lifestyle, they are offered up for sale again to anyone who can pay, or they find themselves in a shelter, or perhaps they are just turned out to fend for themselves.
The Not-So-Cruel Puppy Mills 
I've described above the worst case scenario for puppy mills. They do exist.  However, there are puppy mills that operate within the law, meaning that they provide adequate food, water and shelter.  But don't get all warm and fuzzy here - these dogs are still being treated like livestock.  Their main purpose in life is to produce pups and provide income to the puppy mill owners.  These people don't have just a couple of dogs on their premises - they have many.  The dogs are not pets.  They are money-making products, period.  The puppy millers don't care where the pups wind up - their only concern is how much money they can make.
Backyard Breeders
A backyard breeder, while not a puppy miller, is someone who breeds their dog without any regard to its health or temperament. They usually have "pet" quality dogs, and have no clue as to what constitutes a breeding quality dog.  They do no health tests, have no idea of what is in the dog's ancestry (i.e., health problems) and use any convenient stud regardless of whether this stud is worthy or compatible.  Often, they have one litter to "show the kids the miracle of life", or "it will calm the bitch down", or "we want a pup just like FiFi", or (my least favourite) "we want to get back the purchase price of our dog".  And if that is not bad enough, they either hand over their entire litter to a pet store to sell to anyone who has the money to purchase a dog, or they advertise them in the local newspaper and sell to ANYONE who has the money. They don't care where their pups go. They are only interested in the money. And who suffers?  Well, the pups and the new buyers, because quite often these pups will be riddled with health and/or behaviour problems.  And the new owner often will have the same misguided thoughts as the original backyard breeder and breed their puppy  - thus another backyard breeder is born, and the vicious cycle is perpetuated.
You Can Make a Difference!  
Do you really want to support such operations?  I don't think you do.  But every time you purchase a puppy from a pet store, you are enabling these people to continue to breed these poor animals.  And please don't think you are rescuing that poor puppy.  For when you purchase that puppy, another will just take its place. You must refrain from purchasing any puppy or kitten from a pet store, so that these puppy millers no longer make money.  If there is no money to make from breeding (exploiting) animals, then they are not going to breed them.
Apply Pressure to the Pet Stores!
Also, when you see puppies or kittens in a pet store, don't buy ANYTHING from that store.  Tell the store manager/owner that you will NOT buy any products from this store until they cease selling animals.  Tell them you will tell all your friends too.  If we all pull together and boycott stores that sell animals, then we can stop puppy and kitten millers.
Breeders are Snobby and Expensive!
This may seem true at first glance.  Reputable breeders may seem very snobby.  They ask you questions about yourself, your home, your lifestyle.  They don't just immediately hand over a puppy to you when you ask.  They make you fill in questionnaires and it feels like you're adopting a child.  You have to wait for this puppy; have to sign contracts and give assurances.   And sometimes you might even be refused a puppy. If you are refused a puppy, it may be because the breed of dog you are interested in will not be suitable for your lifestyle.  It's not fair to you or the dog to be placed together if you won't be compatible.  Some breeds are just not suited for city life in apartments, or people who have small children, or people who have busy lifestyles.  That is why breeders ask you questions about yourself - they want to ascertain among other things, if their breed of dog would be suitable for you.  Also, these questions help  breeders determine what temperament of puppy would be most suitable for you.  So, they are not being snobby; they are just wanting the best match for you and the dog.  And reputable breeders care - they care where their puppies go, and they  care for the pup's entire life, not just until the money changes hands.
When you buy from a reputable breeder, you are embarking on  a relationship that will last the entire life of the dog and beyond.  Your breeder is there to assist you with the difficult problems that can arise; they will help you with diets, training, health problems, etc.  They care as much for the dog as you do. 
Breeder's Rarely Cover Their Costs
Why does it appear that dogs from breeders are more expensive? Expenses associated with raising quality puppies are too numerous to mention for the scope of this article.  Briefly though, expenses include, but are not limited, to: health clearances of breeding stock, conformation titles, obedience titles, other titles, maintaining kennels, education, vet care, registrations and stud fees.   All of these things take money, but in the long run, it is you, the buyer, and the puppy who benefit from the diligence of your reputable breeder. 
Dogs and kittens should never be bought on impulse.  It should be a well thought-out decision.  Pet stores cater to impulse shopping.  Puppies and kittens are not a pair of shoes, they are living, breathing creatures that can feel pain - and believe me, these poor animals suffer unspeakable horrors.
So, although you may have to jump through a few more hoops and wait a bit for that puppy, please BUY from a breeder NOT a pet store.
The Alternative
If you can't afford to buy from a reputable breeder, then go to your local shelter and adopt a pet and save a life. 
Don't be Deceived!  
So, you think you know what a puppy mill or backyard breeder is and you cagily ask the friendly pet store clerk where these pups came from.  The clerk gives you a sob story..."the pups came from this wonderful breeder down the road who would have sold them herself, but she had a heart attack and couldn't take care of the business anymore, so she entrusted them to us", or some other variation of the pet store trying to look like the Good Samaritan.  Don't be deceived!  No reputable breeder would ever give over their beloved pups to a pet store.  A reputable breeder has many breeder friends who would gladly help them out in their time of need.  Remember, a breeder always wants to know where her puppies are going and how they will be raised and treated.  A pet store doesn't care.
Also, no matter if the pet stores is a giant superstore or a small business - if they sell animals in their store, they are facilitating puppy millers and backyard breeders.
If I can stop just one person from buying from a pet store after reading this page then I've been successful.
Spread the word!  Stamp out puppy millers and backyard breeders! 
Article written by Debbie Tripp (Kimberlite Kennel)