In a 2-3 years time,
A $10 Android prepaid phone (which is subsided by the prepaid carrier) will have a 5" screen and 720p screen resolution.
p.s. the Moto E was on sales for $10 on Best Buy. Look at its specs:
http://www.gsmarena.com/motorola_moto_e-6376.php
Available. Released 2014, May
Size 4.3 inches (~63.0% screen-to-body ratio)
Resolution 540 x 960 pixels (~256 ppi pixel density)
Qualcomm Snapdragon 200
CPU Dual-core 1.2 GHz Cortex-A7
GPU Adreno 302
MEMORY Card slot microSD, up to 32 GB
Internal 4 GB, 1 GB RAM
It's almost comparable to a $199 Ipod Touch right now but just for $10.