Coming from the USA to CDG airport, then to SJPdP to begin Camino. Shall be traveling with an iPhone. Have heard that replacing the SIM card is the way to go for using the phone in Europe without incurring excessive charges. Am told they can be purchased in the airport from vending-like machines. Shall appreciate and and all info shared re this topic. Are there good, better, and best versions of SIM cards or are they all the same?