There are no alcohol taxes there man, and with the exchange rate US money went miles.
My first night there I offered to take our guide, his fiancee and a park ranger to the Boma for drinks with my wife. I saddled up to the bar and told the bar tender I was buying us all a round of drinks. After he told us they prefer US dollars to 'rands I slid him two twenties to open a tab.
Everyone else laughed there asses off because they said it was enough for the entire evening. Which it was, with tip even.