Site visited in March 2012. All prices were valid at that time with utilization of official peso - dollar rate of exchange. Currently you can exchange your money on black market when rates are much more convenient.
In March 2012 it was extremaly expensive place (like the whole Argentina), normal entry ticket costs 50 ARS (which is around 12 USD) but as it is located in remote area (no public transport) you should combine that with an organised trip (from nearby Perito Moreno town the trip costs 220 ARS per person, around 50 USD). If you don't want to stay in Perito Moreno overnight (the place itself has limited accommodation, especially on weekends !) this should be planned carefully - there are limited transportation between Caleta Olivia (on the coastline) and Perito Moreno as well as on legendary Ruta 40.