Buying my mom a smartphone (AT&T), suggestions?

Howdy folks, I'm buying my mom a smartphone because she wants to use Chromecast and use it for navigation in the car. She's not tech savvy at all (I'm amazed she knew about the Chromecast).

She's on AT&T with no plans to switch. I was thinking the Moto G? It is compatible with AT&T's bands, right? Are there any other cheaper options to consider? Is there anything around that price-to-performance range that has LTE?