I have the need to interject here. There is a big difference between what I would call someone who cares for the pets they are creating and selling on (a good breeder) and someone who is merely interested in a quick buck.
Sadly more than half of the pups I see these days are sickly, undernourished scrappy little things which have come from people who either don't know how to care for a bitch and her litter or don't actually care about the pups at all except for the money that they will generate.
People MUST see a mother WITH her pups, not just a dog they are shown in the garden. Use common sense, try to see a litter more than once if you are keen to buy a puppy (even better, get a dog from rescue!) and if you lift a puppy, does it feel chunky and solid?
Talk to your vet before you get a dog. Question everything a puppy salesperson says to you. If the puppy has been vaccinated, check the card and the postcode of the vet who vaccinated it, you would be astonished how many puppies I see that are bought locally but were vaccinated in Wales.
I'm going to say this out loud, there are vets who vaccinate puppies for these people and seemingly don't care about the trade. I do care and urge people to have a look at this page for pupaid - http://www.pupaid.org/wheresmum
Sorry if I am ranting a little, this is something very close to my heart. Far too many dogs live in misery so that people can have a designer puppy that, a reasonable proportion of the time, they won't even bother to keep when it grows up.
Well said Steve a subject very close to my heart too - there are far too many greedy, ignorant and uncaring people producing puppies, poor scrappy little things with heart problems and other defects caused by in-breeding or breeding from bitches carrying genes for hereditary problems. You can't always tell by looking at them! However the problems lead to huge expense and often misery for the dog and heartbreak for the owners.
However, a good breeder who understands what they're doing, takes advice from a good vet and cares about their reputation and the puppies they produce is a treasure. It's well worth paying a premium for a properly produced puppy. Even a cross-breed costs money to produce properly.