In Finland and Estonia it was very cheap and simple to pick up a SIM card for my unlocked phone. They sell them at newsstands, € 5.00 at HEL airport, € 2.95 in Estonia (plus that card earned money for incoming calls, so I left after two days with about € 5 on the card). Every country has different rules, so this thread is for suggestions and info on buying cards. To start with- I'll be in France for a few days, I'd like to get a card, but it will get very little use, so I don't want to spend over € 10 or € 15 for it. Is that possible? And is there anywhere to buy it when I first arrive at CDG, or at a major train station in town?