From Ezeiza International Airport.

Option I: Transfer Company ($55 pesos)
This alternative is economical only if you’re travelling alone. Inside the airport there are some transfer companies (the best is called HI Transfer). This company has a shuttle bus which goes to its own terminal in Retiro (Puerto Madero) near the bus terminal.
Once you arrive at Retiro, you need to cross the park "Fuerza Aerea Argentina ", and make your way to Retiro subway. Once there you need to take Line "C" or the blue line. The cost is $2.50 pesos
Once on the subway, travel 6 stations (Saint Martin, Lavalle, Diagonal Norte, Avenida de Mayo, Mariano Moreno, Independencia.) You need to get off at Independencia, walk to the end of a long corridor, and exit via a staircase.  Once outside, you will find a Shell service station on the corner of Estados Unidos and Lima. Continue walking down Estados Unidos until you reach Salta (only one block), turn left, and look for us at 990 Salta.

It is between the Estados Unidos street and Carlos Calvo.
In short, walk to the subway station, take line "C", get off at Independencia, look for Salta street, and walk two blocks from until you arrive at PAX.

Option II: Taxi (from 150 to 170 argentine pesos) - For two or more people

If you are 2 or more people, the best option is to take a cub.

Once you arrive at the airport, get out to the street and there will be a lot of taxicubs offering their service. Before you get in, negociate the price (arround 80 or 90 pesos would be fine) and tell them our address: Salta 990 between Estados Unidos y Carlos Calvo.