Tello, 100 minutes talk/unl text/a gig of data, $6. Uses the tmo network. You can also port your number to Google voice for a $20 one-time fee and have unlimited voice/msgs, as long as you have wifi service. Uses the Voice app.

Tello is my second number, few years now, had no issues. Used to have GV back when I had no money as a teenager, and would use my tablet as a phone. Worked surprisingly well.