We called from the room at Temp a couple times to AZ to check on son's visit with Gramdma, while not cheap, it worked out to about 2 bucks a minute, no additional fees.
We got nailed royally on that last year. Typically we buy the phone cards at the gift shop, but they were soldout. Used that pay phone and bills were over 250 bucks. Complained to visa, they reversed the charges, but told us if the vendor provided the recipts, we re were shit up crick. 12 months later, no sign of the recepits from mexican telecom. Just an fyi.