At PetSmart, there is, at most, four baby rats in one tank, and I usually only see two together, which is how it should be. And the gerbils and hamsters almost always live alone in their tanks, unless they're of the dwarf varieties, and then they have cagemates. They have nice bedding, a variety of food, and the lights on the cages aren't too bright.
I, after joining several rat-based forums/communities/whatever, was pushed into a situation where I felt severely judged because that was the environment I had purchased all of my girls from. I had written it off as not knowing anything at the time, and had decided that I wouldn't do it again.
Then I walked into PetCo.
Holy fucking shit, that place is the saddest pet environment I have ever walked into. The rats all lived cramped together, fifteen to twenty of them in a single tank that was about twice the size of the ones at PetSmart. Gerbils and hamsters were five or six in a tiny tank. All the tanks were so bright, I had problems looking into them, so I can only imagine what it was like for the poor little rats. They had one water bottle and one food dish with those delicious lab blocks. Not that there's anything wrong with lab blocks, I mean, I add them to my rat's dry mix since Demyx is totally into them
So I'm sticking with PetSmart. Because they aren't devil spawn. And because they treat their rats nice.