Car Rental, Santiago de Cuba
Due to knowing a Santiago resident I became familiar with the common Santiago way of transport, the motorcycle. For the more daring under you, try it. It's a quick and very cheap way of transportation. Most trips will cost 10 cts. Just wave down any motorcycle you see passing by and enjoy your ride.
Some will try to let you pay $ 1.- but a little persistency will bring the price down to the going rate.
Besides the Viazul bus options. There are plenty of trucks and cars leaving for neighbouring cities from Calle 4 near Parque Ferreiro. It is mainly for Cubans and the truck's seating can be uncomfortable. They will also try to charge you more since you are not really supposed to be using this type of transport. However, if you are patient you will eventually find someone willing to run the risk. The price for a car will be higher than Viazul but the cars and trucks are always leaving throughout the day as opposed to twice a day for the Viazul bus.