The legal drinking/purchasing age is 18, however enforcement is lax. But in bars and clubs, expect hash treatment if your not the legal age. As the age limit is a lot more enforced in those places. As bar and club owners can get fined.
Bolivia Altiplano traditional alcoholic drink is chicha de colla, a whitish, sour brew made from fermented corn and drunk from a hemispherical bowl fashioned from a hollowed gourd round-bottomed so you can't put it down. It's customary to spill a bit of chicha on the ground before and after drinking it as an offering to Pachamama, the Inca earth godess.
Singani is a grape liquor that's mixed with Sprite or ginger ale with lime garnish to make a cocktail called chuflay.
Tarija is located at 1924 meters above sea level, and is known for its wine-making, vast vineyards, and award-winning wines. Hence you can visit and taste wine at its beautiful wineries, such as: Campos De Solana, Kohlberg, Casa Vieja, Valle De Concepción, and Casa Real, where the famous Singani is made.
Juice bars appear at most markets. Shakes either with water or milk are 2-3Bs. Locals can be seen drinking Vitaminico, an egg, beer, and sugar concoction or "Vitima" which includes coca leaves.
Licuado - Water or milk blended with your favorite fruit combination. A big spoonful of sugar will be added unless you specifically ask them not to. Try the milk and papaya licuado.
Vitaminico - Don't ask what's in here. Many fruits, milk, sugar, a shot of beer, and, if you wish, a whole egg with shell.
Mocochinchi - A drink made by brewing peaches and spices together in water. Very good but some people are turned off by the shriveled peach which is typically served with each glass.
Api - A traditional corn base drink usually found in the open-air markets. If you didn't know it was corn you'd never guess it though because this stuff is good.
Chicha de camba, chicha de maiz, chicha de mani - non-alcoholic chichas, made from corn and similar stuff. Very popular in the East of the country.