Ever been in a New York City Taxi? If yes than you will be no stranger to a Bogota taxi driver that prays on tourists, if you don't speak Spanish you won't be able to argue with them when you notice you passed the same intersection three times.
The only way to get even is slam the door when you get out. (the doors are really thin and cheap and they hate when you slam the door and the window falls off the track)
But on the bright side taxis are a great bargain and they probably need that extra $0.50 cents more than you do.
Unique Suggestions: The taxi meter will have a meter that will be set at 25. When you get in the cab make sure the driver sets the meter or you will start out paying for the last guys fare.
When you are at your destination the meter will have a total. Look at the total then look at the chart in the taxi. (they all have the charts)
From the total on the meter the chart will tell you what the fare will be in Pesos.
They are allowed to charge an extra 1000 pesos at night and on Sundays.
ALWAYS chose a yellow taxi with a two way radio, (it will have a small antenna somewhere on the car, NOT a regular car radio antenna) this is for security. You can also always call for a taxi from your hotel, apt. etc. mall etc., all calls are recorded and documented.
Fun Alternatives: Your only alternative is a bus.