Kathy has a friend who's thinking of moving to Consumer Cellular. Leo says that they are an MVNO, reselling coverage from another carrier like AT&T. It should work as well as the carrier and often they are a great deal.
However, they may also have data caps and even throttle data after the 1st GB. Leo says the deal may be better for voice plans rather than data plans. Another option would be a former sponsor Ting. The chatroom suggests Republic Wireless, which is another great option. If Kathy doesn't mind buying a Google phone, Google Fi is a great choice too.