In Botswana home currency as well as the SAR’s rands are accepted for payment. So, if you are planning to visit the South African Republic or at least one of the neighboring countries, you can buy only rands.
Hitchhiking is widely used. So widely that it has become a paid service with standard tariff of 5 US dollars for every 100 km. So, when you are catching a vehicle, always ask if it’s for free or payable.