I have a 6.44" Sony Xperia Z Ultra that only works with T Mobile or AT&T so in January I started with T Mobile's $30 pay as you go plan with unlimited data and text but only 100 minutes voice calling. I then switched to AT&T last month to their $30 Monthly Unlimited Prepaid Plan that includes 30 days of Unlimited Nationwide calling, and Unlimited Nationwide Text, Picture, and Video Messaging but only wi-fi internet that works better for me since I am almost always near a wi-fi spot using our Comcast Xfinity wi-fi. With T Mobile half the time I had no phone service at my home.
Comcast wi-fi 
