First off: where do you live?
I'm asking 'cause if you live near me (or Cincinnati/Florence Kentucky) check out Jack Aquarium and Pets. They have pretty healthy bettas and some really pretty ones. (There's like 2 yellow multi-colors down at the Florence location).
And World of Pets (down in Florence) has a wonderful selection of betta supplies (tanks, heaters, FOODS [my bettas now have like 5 kinds of foods. lol], plants, everything).
But if you don't... You can order stuff from Jack's i'm sure... As it is, people order stuff from jack's through my cousin and he ships it to them..