Hundreds of Buses or Colectivos or better known under "Rutas" fill up the streets. The trafic is some how chaotic, but it functions perfectly, and it may be a lot of fun taking part of it. They run regularly and during non-rush hour, they can be a cheap way to get to center. The 1.50 pesos fare must be in exact change. Watch for pickpockets when colectivos are crowded.