Public transportation in Viña del Mar is outstanding. In the U.S. we have always heard that it the public transportation systems were better in other countries and that is definitely the case in Chile. There are 4 types of public transportation available to everyone in the urban region of Valparaíso:
1. We have Micros (above) which are the buses. They are super cheap ($.25-2.50 depending on how far you go;the latter price I paid for a two hour trip north) and very available. Unlike the U.S., you can catch a micro going to a populated place (such as the mall) practically every minutes. I would struggle to say that there as many buses as personal cars on the roads.
The Metro is the region's subway system. It runs from the edge of Valparaíso to the countryside northeast of Viña (an hour long ride). This is a little more costly to get around, however still less than $1 if you already have the card ($8). I used to use this more when my girlfriend lived along the metro, however have only used it to get to Valparaíso since she moved.
Colectivos (above) are my favorite mode of transportation in Chile. They run like a Taxi where they can bring up to 4 people yet function like a bus because they only run along certain routes. Depending on the time of day it can cost between $1-$2 for a ride per person. These are my favorite because when I come back late at night, I don't want to have to stand up on a bus for a longer period of time, whereas I can take a colectivo which provides privacy and quicker transportation. It is also easier to start conversations with the driver being it is is more private (less embarrassing).
Taxis in Chile are very similar to those in the U.S. where they will take you wherever you need to go. They are also alike in that they are very expensive. In all honesty I have not used one because I live so close to a colectivo/micro route. This is more popular option for women because they can be dropped off right at their door.