Here's a dirt-cheap GSM cellphone that's available everywhere in the world except the United States: the Motorola C116 is a basic $39 handset (or get it unlocked for $70) that Motorola developed specifically for developing countries. The bare-bones candybar has a monochrome screen and is good for five days worth of talk time on a charge. It reportedly does all of its basic tasks quite well, including sounding better than most other phones. Too bad it's not officially available in the United States.
However, the C155, its slightly more well-equipped brandmate, is available for $29 at Wal-Mart, Target and elsewhere, and it has a color screen. Not a bad deal for those who just want to talk on the phone without any frills.