I'm going to be studying in Madrid for the fall, and I'm trying to figure out what will be the cheapest way to call home. I've heard about renting a cell phone over there. Since I'm only going to be there for a few months, is it worth it? or should I just buy calling cards before I leave? Any ideas would be appreciated... (I'm also planning on traveling across Europe after the semester ends--do you know if I can rent a cell phone that Icould bring everywhere with me?)