if your account in the u.s. is with bank of america, you can use ANY Santander, Serfin, or Scotia bank in Mexico, with no service charge. After @ 25 years of traveling all over this country, we have never had a problem using ATM's (except that they often run out of money--especially in smaller towns, and on weekends)--also found that the exchange rate changes via the computer controlling the ATM, so is often more updated than using the teller at the same bank (this involves a long, boring story about a brother-in-law who didn't trust the ATM and was convinced that the teller would give him the most up-to-date exchange rate---which did NOT happen-lol). If you are very concerned, always ask for a receipt, so you can compare changing exchange rates, and also use to contest any errors that may occur