Buses, which are called Colectivos in Argentina, are the most frequented forms of public transport in Buenos Aires. There are more than 200 lines that go on every five minutes, and they operate all day, every day. You can also use the Metrobus, which uses more exclusive routes and is generally quicker than ordinary bus lines.
The regular ticket price for the bus is 23 ARS.
By the way, the bus transport system of Buenos Aires is called the AMBA.
You can travel freely throughout Buenos Aires, because the town is safe and the public transport system is more than efficient.
photo credit: Leonardo Miranda