Travelling by train in Botswana, be aware that train arrival times always show delays, and buy only First Class tickets. Lower class cars are in horrible condition.
Don’t pay fare to the bus driver hoping that he will depart sooner without waiting other passengers. The driver will take as much passengers as possible anyway.
The most budget friendly way to have a bite is a local fast food. It will cost you only $5. And if you buy food in supermarkets and live in tent, $15 would be enough for several days.
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.