DONT go to the exchange across the street unless you count the money and check it right there. I got ripped off last trip. Didn't want to count it for the world to see and have used it before several times no issue. Got back checked the receipt for what I was supposed to have and bam, she kept $30 for herself
Exchange We used all US dollars for tips and if we went off the resort we used the credit card and they charge the peso amount and your bank will give you the current exchange rate. We went to Harley Davidson store downtown and there exchange rate was 13/1 and that day we had seen it at almost 16 somewhere else.