Products such as this claim that they have beneficial bacteria in them that will aid you in kick starting your cycle. Somehow, this beneficial bacteria survives on a store shelf, with no oxygen, and a depleted portion of ammonia (its food source). Sounds bogus IMO
I wouldn't buy it. Either cycle the aquarium yourself the natural way (fish in) bettas are pretty hardy fish and you should have no problems at all if you are responsible with your tanks chemical levels, or ask a friend for some filter media.