I personally wouldn't get a puppy from a puppy mill/store. I have many reasons that I prefer not to share...
It's a very small, caged enviornment and think it'd be really hard to potty train. They let their dogs sit in their urine/poop and that is disgusting. And they put more than one animal per cage which is wrong. But I think you also rescued the poor puppy and if you can give it a better home/living environment than more power to you. I hope you and your puppy live happily ever after hehe..