If you want to go really, really cheap, get the Moto E. The new Moto E delivers a quad-core processor, 4G LTE and Android Lollipop in a small package for only $149 outright. The screen is bigger than last years Moto E at 4.5-inches, but sadly offers a low 960 x 540 resolution. The first model had dual front facing speakers, but this model that was removed in favor of a bigger screen and 4G LTE. All of that is only $149 outright.
The Moto E 2015 already runs the latest Android 5.1 Lollipop, and has plenty to offer for a first time smartphone buyer, or someone on a serious budget. If you have to, get this, otherwise spend $30 more and grab the Moto G, you'll be glad you did.