If you're looking for a simple cell phone on Sprint, the Samsung M400 could do the trick. Configured as a flip phone, the silver handset has a small external display that shows the battery level, time, and alerts. Inside, a 2.4-inch screen navigates you around.
The M400 has a 1.3-megapixel camera launched by a dedicated hardware button on the side; there are personal essentials like an alarm clock, speakerphone, and browser; and in-case-of-emergency (ICE) settings round out the intentionally limited feature set. It also supports Bluetooth 3.0 for pairing with headsets and transferring photos.
As for the gritty details, the M400 stands 3.8 inches tall by 2 inches wide by 0.7 inch deep and weighs a solid 3.7 ounces. Its 1,000mAh battery has a talk time rating of up to 4 hours (that isn't much) and up to 10 days on standby. According to FCC radiation tests, the M400 has a digital SAR value of 0.66 watt per kilogram.
Sprint is offering the M400 for free with a new two-year service agreement.