I never got one for my daughter when she was a teen - no justifiable reason to. I was at home fulltime and she could call from school/her friends if needed. When she was older and could sign and pay for her own she got one.
I suspect my view may be the same with my son. But if I were to start working out of the home and he was a teen, I may get him one just for check-ins and emergencies. Payphones are few and far between around here and if he wasnt at home and we needed to be in contact, thats the only reason Id agree to one. I would send/receive texts at work but possibly not calls.