You need 28 packs - you choose how many of what packs you want - if you don't want a particular pack, you simply don't ask for it. My usual shopping list is 7 each of the strawberry, raspberry and banana. Then 4 cran/rasp bars and 3 peanut, and then viceversa on the following week. Although that said we are being restricted on bars - so having 2 each of those bars, 2 fruit and 1 toffee (the lemon tastes like a chemical toilet so avoid that one - not that I know what a chemical toilet tastes like, but I can guess!!)
Hope that helps?