If you want to get the most bang for your buck while traveling in Argentina, stash the cards and bring all your spending money in cold, hard cash. And then sell it. As of late, the official exchange rate has been hovering around $8 Argentine pesos to $1 USD, while the blue rate, which is what you get if you sell actual bills, is upward of $12 pesos to $1 USD.
Yeah, that's a 50 percent difference. Cash is king.
Asking at any café or tourist locale about where to sell dollars, accompanied with a knowing look, will get you headed in the right direction, whether a Western Union or cueva, as they’re called. Another place to sell: On pedestrian thoroughfare Florida Street downtown, where people unabashedly yell about buying dollars. While offering your goods here might lead you up a dimly lit stairway to a small, Spartan office and get a slasher movie looping in your head, most of these people really are just looking to do business. It stands to be noted, however, that petty theft is prevalent in Argentina, so if something feels particularly fishy, trust your gut.