Many people fly into another South American country, such as Argentina, Brazil, Chile or Peru, and travel overland to Bolivia, which generally works out to be cheaper. Be prepared for delays, cancellations and general unreliability. Bolivia's road network is not good, mainly because of the lack of paved roads. Most long-distance buses depart in the evening and travel through the night. If you want to see the countryside between towns, you're better off catching a truck, a popular mode of transport among campesinos.
Trucks are half the price of buses, but can be rough going.
Bolivian railways have been recently privatized and passenger services have been drastically cut back. We encourage you to verify any critical information with the relevant authorities before you travel. This includes information on visa requirements, health and safety, customs, and transportation.