Mt Mature Looking For A Cell Phone For My 15 Year Old, Only For Texting, Or Text And Minimal Calling Minutes?

Looking for a cell phone for my 15 year old, only for texting, or text and minimal calling minutes? - mt mature

Mt son wants to do a lot of text, but is not yet mature enough to know, how to deal with call minutes and would probably bill. Is there a monthly plans, unlimited SMS and prepaid minutes?