I bought Darby from a place called "The Wet Spot" and was delighted to find them in little 1/2g mini-tanks. It's the only time I've ever seen Bettas with some swimming room and not stuffed in a tank full of guppies or other inappropriate fish. I learned later that the person who supplies them with their bettas also works in the store, so I guess it stands to reason. 
I wouldn't buy from anywhere else now.
I wouldn't buy from anywhere else now.