Petco in my town is ok. However, they don't dispose of the dead Bettas very fast. The water's clean, but a dead fish in it... duh... that makes sense, huh? The other Petco in a town about 7 miles away is about the same, but doesn't stock much other than VT's and a few CT's.
I haven't been to the Walmart cuz it's 22 miles away. However, the local town pet store that's been here before Petco keeps their Bettas in tiny wall hanging cups half the size of Petco's with NO lids. While I was there I was gently tapping on a Bettas cup to get him to face me or turn the other direction, and one below jumped out of the cup at my arm and fortunately landed back in the cup! I said, "Whoa dude! That's not really a good idea!" I was wondering how often they have to pick up dead Bettas that have jumped out and landed in their overflow trough below the cups?!
I found a really nice aquarium shop in the other town that is stuck back off the main drag. Small, cramped quarters, but everything is being taken care of, EXCEPT FOR THE BETTAS, once again. They're all in glass bowls the size of the Petco cups, with no lids, and stuck on a bench, stacked on top of each other! However, all the females are in community tanks loaded with plants. I couldn't even see them, they were all hiding in floating moss like plants. They even had a couple female Betta Imbellis. Wow.