I have a Trac phone...they were the only ones that would work when our area was hit by a tornado years ago....inexpensive...we only use it for Dr. visits, if our old car should break down and they work when the electricity is off.....
We use Ting mobile for our kids, which I find super flexible. Their "flex" plan is $10/mo for a line, and then it's pay as you use for pooled voice/text/data. I have data turned off on most of our lines, and usually end up spending $3-6 on voice and data each month for them - for a couple hundred minutes of calls and 400-600 texts. https://ting.com/