I can start by saying: Take your cell phone with you when you travel overseas but only use it if you have an emergency! The cell phones carriers charge exorbitant amounts for calls and data when you are roaming overseas. And we are talking about rates per minute starting at US$1.99, or US$2.50 when you are on a cruise. Do the math!
When planning a trip, I researched the best options available - satellite phone, cell phone rental or SIM card? The price for satellite and cell phone rental overseas was almost the same as using my own cell phone on the trip. The SIM card was the most convenient and cheap option for the trip. You might be asking: What is a SIM card? A SIM card, also known as a subscriber identity module, is a smart card that stores data for GSM cellular telephone subscribers. A SIM card can be switched easily from one phone set to another.
So when I was going to Brazil last March, I used http://www.rebelfone.com/ to rent a GSM phone (a basic Motorola phone) for US$1 a day and the Brazilian SIM card for US$15 for 30 days. Incoming calls and local text were free, local outgoing calls were US$0.80 a minute. A few days before my trip I received the phone and the SIM card with a Brazilian number, inserted it on the phone. Once I arrived in Brazil, I turned the phone on and it was ready to make and receive calls. When the trip was over, the total cost for the phone, with a lot of talking in Brazil was US$150. If I had used my carrier for the same usage I would had paid around US$700.
So, how people in US can call you during your trip? Well, companies like Rebelfone offer a service that connects your cell phone to your international SIM card number and it costs US$0,49 per minute. I have a Skype number in US, so all I had to do was forward my Skype number to my Brazilian SIM card number and when people called me from the US, they paid as a local call, I paid US$0.05 for Skype to call Brazil and the incoming call was free on my Brazilian rented phone. Pretty cool!
There is a SIM card for every country you can imagine, they also have packages for a group of countries and they also have World SIM cards available. The best place to shop for a SIM card is http://www.telestial.com/
If you have a phone with internet, you can download Skype on your phone (or get a Skype app) and whenever you have a wifi connection, your phone can call and receive calls using your Skype account. Now, this is the cheapest way to keep in touch!