There is no cheaper way, even computer E-mail is more expensive unless the ship has a special deal for employees. I expect though, that the ship doesn't want the service staff spending their time on the phone. The ships don't pay very good, about $20. per day, the service staff is expected to work around 18-20 hours a day and get very little off time to themselves. They work for gratuities from the passengers. If your girlfriend spends too much of her working time on the phone, she won't keep her job very long, plus she will be giving up most of her paycheck making those calls. Most of we cruisers use our cell phones preset up with our providers for international calling, when the ship is in a port. That seems to be the least expesive way. Most cell phones charge a fixed rate plus so much a minute. You will need to limit your calls to save on charges.