Well, for one thing, $20.74 for the same stuff on Amazon Prime (sold directly by Amazon with free shipping if you have Prime or spend enough $$):
Amazon.com: Purina Fortiflora Feline Nutritional Supplement Box, 30gm: Pet Supplies
That is how I just bought it. But I swear I must have the only cat in the world who doesn't find the Fortiflora irresistible. When I sprinkled that on her food a couple times she completely ignored the food.
As another shot at this I just bought a bottle of AddLife from Wysong, which is a 9oz bottle for $17.49. I believe that sounds like a lot more product for less money. It has not arrived yet so I don't yet know if it will go over any better. AddLife is suitable for both dogs and cats if you happen to have dogs around.
Wysong Addlife™ It appears to be an update of their older species-specifc F-Biotic and C-Biotic products, although they still sell those as well. I chose the AddLife because the description sounded more appealing.