The traditional gratuity to safari guides, camp staff, mountain porters etc. is not included in the price of your tour but is completely discretionary. You should tip in accordance with the level of service you have received.
The following guidelines are generally accepted practice (per safari group, per member of staff): Safari guide(s) – USD 10-15 per day; Cook (on camping safaris) USD 7; tented camp, lodge or hotel staff – USD 3-5 per day, as a pooled tip to be shared among the housekeepers, waiters, bartenders, etc.
For porters and waiters at hotels and for taxi drivers in cities, the customary tip is approximately USD 1, and tipping in one dollar bills for porters and waiters is greatly appreciated. However, beware of unscrupulous people who try to exhort extra payment from unwary passengers just for shuffling their bags around. They are usually to be found at airport arrivals zones – anyone helping you at a safari lodge or tented camp will be a legitimate employee of that establishment.