Best Buy offers the T-Mobile Prism II Prepaid 3G Android Smartphone, model no. U8686, for $29.99 with free shipping. That's $20 under our mention from Black Friday and the lowest total price we've ever seen for a T-Mobile prepaid Android smartphone. (It's also a current low for this model by $20.) It features a 3.5" 320x480 display, 3.2-megapixel camera, FM radio, up to 8 hours of talk time, and Android OS 4.1 (Jelly Bean).
Note: Orders placed by December 20 at 3 pm ET are guaranteed to arrive by Christmas.