Hi Lauren,
This is my experience, a week and a half ago on Calle Florida:
Went to the most respectable looking person advertising "cambio".
I asked him what is tipo de cambio blue was. Bartered a bit. Generally you should be able to get
at least the blue rate (
http://www.dolar-blue.com/ ) less 0.5.
100 USD bills are prefered. The more you change, the more bargaining power you have to get to the "compra" rate listed in the dolar blue web site..
Experience number 1 : went inside the mall to entrance of a stair case. He counted out around 5000 pesos in 100 peso bills. I recounted them and flipped through them individually looking up through the light to make sure there weren't any fakes. I assume you know how to check (?). Pulled out my money . Gave him my bills. He checked them and we thanked eachother. I promptly got in a taxi.
Experience number 2 : another exchanger brought me inside into a travel agency and someone else from the office changed the money. (a smaller amount this time ) Once again, I checked each bill quickly up at the light and then gave my money.
Experience number 3 : different exchanger brought me inside a different travel agency. Same scenario as experience number 2.
advice :
-go with a friend
-ask if the exchange is done in a negocio or office or in the street/staircase etc. Favour the exchangers that bring you to an office/store for the actual exchange for security reasons
-check every peso bill individually up at the light (quickly) before handing over your USDs
-if you have just changed a substantial amount - exit and get into a taxi asap. No milling about .
there you go , that's my advice if you can get to Calle Florida.
The experiences described are mine.......yours might vary......