What is a SIM card?  A SIM card is actually a smart card inserted into a cell phone that holds personal information relating to the subscriber such as the subscriber's PIN number or stored phone numbers.  SIM is the acronym for Subscriber Identity Module card.

When I traveled a lot from different countries, I had a SIM card for each country.  Once I landed say from the U.K. to Norway, I would just pop out my UK SIM card and replace it with the one from Norway.  Each of my cards had my contact information.  I found this very useful.

Prepaid SIM Cards are the way to go.  You buy a specific amount of time.  You set your budget so there are no surprises.  If you need more time, you can add it to the cards later. There are two types of prepaid communications solutions for the traveler who wants to stay in touch.  There are the country-specific solutions and the other is to meet international solutions. If you want to go the lease expensive, then the country-specific solution is the least costly way of making and receiving cell phone calls in a specific country.  This allows you to take advantage of the inexpensive local rates in a particular country.  

Providers like Cellular Abroad - One World. One Phone provide you access to excellent international call rates and get unlimited FREE incoming calls in most countries when your purchase their international prepaid SIM cards.