Maybe I missed out on the possible answer to this, but my brain is a bit all over the place at the moment to recall.
I bought quite a few Flying Daggers potions, but they are not showing up when I go battle. I meet the stat requirements for the potions, and they still don't show up. I don't know why. o_O
Thanks! ^_^ I decided to buy a handful since I haven't been using potions that much, and then saw that they weren't coming up during battle. D: The horror!