I will second (or third) the Skype method...YOU need to download the app..the party receiving the calls does not need anything as it goes to their regular phone at 2.9 cents/min

..airplane mode
..wifi on
..Skype app
..dial
..talk

No monthly limits or subscriptions needed. Talk for an hour for less than 2 bucks

Used it in many countries with great results (assuming the wifi connection is decent)