Just to clarify - I never ever consider myself "rescuing" a betta when I purchase it. That's just dumb. But I still stand by my opinion that selling the babies is not much different from selling the adults. With a bit of research they are not hard to care for. People should be doing that with ANY pet they buy anyhow.
As far as buying the best available - I buy the best I can find in my area. My petco keeps pretty good fish. Another pet chain down the street, however, kept their bettas in an absolutely awful barracks system, and I complained loudly about it both in the store and to the headquarters and refused to spend one cent there until the situation was remedied, which it eventually was. We as customers have to be the advocates and that is true whether you are buying a fish or a toaster.