It really hurts me to say this, but
$1 might be a good option for her. I'm just not a huge fan of Mike Calvo, the companies CEO. However, the reasons I have for disliking the company are based on information I can't prove, so won't state in public comments. But all of the products his company offers do exactly what they say on the tin. So your grandmother might find the easy access to social networks, email, and audio content useful.