There are still payphones?
I shouldn’t laugh, I’m old enough to remember “rotary” phones…
You can buy a cheap “pay as you go” smartphone almost anywhere. I just located a Straight Talk LG Lucky Android Prepaid Smartphone at WalMart for $19.82 USD. I’m sure you could find one for less if you tried.
techno883 is right I would think it would be mainly for her own safety.