You're going to pay for mobile data one way or another if you have a smartphone. I'm not aware of any carriers that will sell you basic phone service on a smartphone without a data package. Not even on a prepaid (pay as you go) line.
You may be able buy a basic phone that only does calls and text, and some may have limited internet functionality and not be required to purchase a mobile data package unless you use that data. Those phones are often pretty cheap, so you can use your savings to also buy a tablet for those times full net capabilities are wanted, as long as you have a WiFi connection available. Some tablets do have mobile data radios, but my guess is you'll be required to have a line for that as well.