Where do puppies come from?

I was in a mall today, and that mall had a pet store. Not just a pet supply store, but one that had that row of cages, separated by windows, with puppies in them.  You know the type.

There was a Puggle, and a Morkie, and a Chihuahua, and a Pomeranian (though the people standing next to me thought it wasn't a purebred Pom; I thought it was, but held my tongue).  There was a Bernese Mountain Dog, and an English Bulldog.  The smaller breeds were all $700, but Berner was $1999, and the English Bulldog had a sign that said "Serious inquiries only."

So, where did these puppies come from?