While I haven't tried the Fizz Butter Bath Bomb just yet, Kara's Way has another giveaway just in time for Halloween. (And yes, that means that you have till the 31st of this month -- Halloween (Samhain) -- to apply. They are giving away Fizz Butter Bath Bombs and all you have to do is enter the scent that you like (which makes things pretty simple).
If you aren't familiar with all the scents that Fizz Butter has to offer, then check them out here. Good luck!