The least expensive way to make an international call is done by using a callback company, which works with either a cellphone or landline. A callback company uses a system that connects an international call to an American line so its user can be charged domestically.
A callback system works using a computer, which takes a received call and links it to a domestic landline. After the user hangs up the phone, the computer returns the call and provides a domestic dial tone, allowing international calls to be made at low U.S. rates. Multiple outgoing calls can be made using the same callback number by pressing the pound key.
After a set period, the user is billed, which can be paid automatically through a credit or debit card.