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Ya and even if you find that magical ethical breeder that health tests, dna testing, spay and neuter contract, pedigree papers, vaccines and only breeds a litter or 2 a year. They're also likely to not just sell any pup to you because you got money they'll likely not let you have a puppy unless they know you've done your research on the breed and everything. They also would charge a hell of a lot more then the $600 Op is whining about.
Rescues and shelters are different, shelters are usually subjected to keeping up with laws and inspections, some "rescues" are just businesses started by ordinary people. I would trust shelters over rescues. 
Sad part is that "ethical breeders" are few and far between. Most don't even get licensed and go under the radar. It is very, very difficult to find a good breeder. I'm a vet tech and I've seen even AKC registered breeders continue to inbreed and sell puppies that need to be euthanized before 1 year old due to congenital problems.