Also, T-mobile To Go, is probably the cheapest option after the 1st year.
Just like ATT, it's $100 for 364 days (at 0.10/min) it will give you 1000min for the year. After that if you add a $10 card, it will extend for another year every 364 days.
So Year 1 would be $8.33/month. Every year after that could be as low as $0.83/month, as long as you don't run out of min.
You would have to find out about coverage in the areas you visit though.
* 2014: Sam Galaxy Avant, SE Z600
* 2012: Sam GS3, Nok 2720
* 2010: BB 8350i, Nok 2720
* 2009: Mot i9, BB7520
* 2008: HTC Tilt, Mot i450
* 2007: SE W810i, Sam A707, HTC 8125, Sam BlackJack
* 2006: Mot L6, SE Z520, Nok 6682
* 2005: Kyo 7135, Sam i600, Mot V551, Nok 6230, 6620, SE Z600
* 2004: Mot V300, SE T610, Kyo 6035, Nok 3390
* 2003: Mot T720C
* 2002: Audiovox CDM4000, 9000, 9155GPX, Thera