Have you looked into Spectrum Mobile or Xfinity Mobile? If you have internet through them it is essentially $14 per gig (spectrum) or $12 (xfinity). Talk and text is free while you keep internet with them. Right now I have 4 lines for $56 including tax to share 4 GB across all lines.

It is also a Verizon MVNO so we get good reception when out and about.