Spice tour 
The spice tours offers visitors to Zanzibar an opportunity to tour plantations, to learn about the history of the island and the cultivation of spice plants, and to see the many varieties of spices produced here , your guide will give detailed descriptions of what the various plants are used for. E.g. the leaves of the neem tree were once used as a cure for malaria and indigestion, the iodine tree produces a deep red sap used to fight infection etc.  Other spices include ginger, vanilla, tamarind, menthol and many more.
Price per person:
1 person $25
2-4 persons $ 18