Many many buses come to Barracas (nowadays the cost of the bus ticket is only US$0,30), so this is a very good option.
10 (From/To Palermo)
12 (From/To Palermo)
17 (From/To Recoleta)
22 (From/To Plaza de Mayo)
25 (From/To La Boca)
60 (From/To Tigre)
65 (Ramal B)
95 (From/To Palermo)
100 (From/To Retiro)
102 (From/To Palermo Chico)
A taxi ride from The Obelisk (9 de Julio Ave. and Corrientes Ave.) costs around US$10 nowadays.
A taxi ride from Ezeiza International Airport costs around US$40 nowadays.