For about 5-10€ you can buy prepaid SIM car.
Do not relie on skype, except in port at a internet cafe, If i'm not mistaken, the cruise ships block skype on board.
Using your world phone in Europe, might make you take out a new mortgage on your house.
It's not as expensive as one might think if you remember to TURN OFF YOUR DATA WHILE ROAMING!! I have used my cell phone from Europe to the East to Hong Kong and Australia/New Zealand to the West without astronomical bills. I also use my cell phone at sea daily where service is available.
Mary Ann & Pucci