-__- I am sorry for the pessimistic point of view.
If you get a betta, before you even go to the pet store with the intention of bringing it home, you should have done good research, and made sure that you could provide ideal conditions for it to live in.
If 11 or 12 bucks is too much to keep a betta you "love" alive, then you should reconsider having a betta. With bettas, a cold blooded animal, fluctuating temperatures, and water quality stunt thier growth, damage thier immune system, and everything.
I don't think you would like to be kept in a room with no heat in the middle of winter with the flu,
that is what the betta feels like right now.
I just get tired of kids getting bettas with no knowledge of them, or even
worse, ignoring the knowledge laid out for them.
If they aren't given the proper housing and living conditions, then they are just as good left on the pet store shelf.