If you're looking for a basic phone at a bargain, you may have found it in the Nokia 2720 Fold. Decent call quality and usability are all we'd expect for just $20 from T-Mobile and $10 with AT&T (both with two-year agreements), but the Fold folds in more.
The Nokia Fold's spines are fairly bare. The right spine features a volume rocker, Nokia's proprietary charger port, and a small flash connector for specialized accessories. The left spine houses a 2.5 millimeter headset jack, which is smaller than the standard, but not a major detriment to the phone.