I travel a lot from Palermo ( close to Palermo subte stn) to Microcentro or San Telmo or Tribunales.
I usually end up paying 45/60/35 pesos more or less, one way in the cab for the above 3. Its not cheap!
I also have had instances where the bill when it should have been 60, came to 80 ( Palermo to san telmo). I refused and paid only 60. And the taxi drivers also agree!
By the way, I use 2-3 taxis a day.
When I feel, I am going overbudget, I suddenly go berserk and start using subte for next 3-4 days and HATE IT!