This was never an issue for me in the past when the official exchange rate was pretty stable and BA's rate was very close to it, but this time for a couple thousand dollar dive bill an 18:1 vs. a 20:1 rate was significant. Thanks to those who posted ATM alternatives that return US$, I was under the mistaken impression that the only ATMs that did that that were the standalone ones out on the sidewalks in town.
Those ATM's that dispense dollars come with a huge fee - I did it once at one in Chedraui, was like 30-40 dollars on a $400 withdraw.
That old you think you got a great exchange rate trick cause the number is higher........
Bring dollars with or withdraw pesos from an ATM....