The corner of Fremont and Sinaloa(Capones, my UN favorite place is on it).....across the street from the Pemex.....you can choose pesos or US dollars.....Yes you can use US cards - don't know about Canadian. There is one ATM that gives US dollars - it is on Fremont Street but not sure exactly where. Others give pesos.
What's the app?I have an app on my phone I check and not that it makes a huge difference but when its a better exchange rate I go to the ATM at the Bancomer on Fremont and withdraw funds and it has always equalled or bettered the rate I thought I was going to get. #my2cents