@TheSpoonyBard

You can only buy Occult Fan I and II, the others must be found at certain points in the game. Just for a complete list:

Occult Fan I: Library of Balamb Garden // Buy in Esthar Shop with the proper Tonberry-ability
Occult Fan II: Find in Dollet in the room of the card queen's husband // Can be dug up with Angelo-Search // Buy in Esthar Shop with the proper Tonberry-abililty

Occult Fan III: When first visiting F.H., talk to the fisherman which is seen in the cutscene with the garden crashing into the town. You must go down a ladder near the upper lift station to get to him.
Occult Fan IV: When first visiting Esthar, go to the man whose dog is just running away and bring it back. After that, talk to a certain guard near the residence.