Exchange pesos at Ezeiza Airport

There are actually three booths: one in the baggage claim area (Global Exchange) and two more outside of customs, in the public area (Global Exchange and Banco Nacion).
Global Exchange is a ripoff, they give you something like 10% below fair market rates. Banco Nacion gives you the same fair market rate you would get downtown. The booth is not easy to find because it's not in your direct line of sight as you exit customs. It's around to your right as you walk past the sliding doors. If you don't find it ask someone about it and if Banco Nacion is closed exchange pesos at Global Exchange as minimun as possible.

At the top left side of this page you will have the average exchange rate for euro/dolar for today.