There's an official exchange rate. If you are a tourist and you want to buy pesos, you have to buy at the official exchange rate. Of course, there will be othe

There's an official exchange rate. If you are a tourist and you want to buy pesos, you have to buy at the official exchange rate. Of course, there will be other places that will give you rates that are closer to that the actual market value is. They may be disguised as place selling collectable coins or whatever. At some stores, they may give you a much higher rate if you buy their stuff with foreign cash. USD and BRL are generally accepted. Then there are the 'arbolitos'. They will be the guys shouting 'cambio!' at tourist locations. YMMV with them. Some are legitimate, some may insert some counterfeit currency in the mix. Personally, I never felt comfortable following someone to an unknown location when they know I have cash in my person.