I have a question about Betta fish.?

Ok well I just bought a betta fish and he seems not so happy. I got him from Petsmart and none of the fish seemed to look so good. He seems to have some fins that look wilted on the ends. I hope he's ok. Their fish are just sad. I watch all these videos on youtube and their fish are so beautiful...where would you suggest I could get a good looking fish from?