I have AT&T.. 3 iPhones .. I finally gave up my grandfathered unlimited. DD had 3gb and DH had 2gb. I paid $176 after a 22% discount. DD kept getting close so I called the retentions department to see what they were offering.
I took the mobile share value plan $100 for 20gb with rollover data. $15 for each line out of contract and $40 for DDs, her contract ends 9-17
They got me out of DDs contract for $50 instead of $185 by selling me a flip phone, waived her $20 "upgrade" fee, gave me 1gb Canada roaming bonus on each line.
Wished I made that call years ago.
New bill is $123 plus tax 3 lines 20gb shared