First time poster, but I did a quick search and didn't see anything about this.
I just had a 6 month promotion expire with AT&T which was listed as 'Promotion for FT Msging Unl with Mobile to Any Mobile Calling'. This was essentially $30 off per month, and took my 2 line family account total from $146/mo to $116/mo. If you've never had this promotion, you may be able to get it added via retentions (I did live chat, and they had a retention representative call me back and tell me it was applied to my account within 45 mins. It was a very easy process)
However, they only allow this promotion to be applied once every 12 months. Since they couldn't renew this promo for me, I was offered $20/mo unlimited messaging on my family account instead of the usual $30/mo, and they said that it is good for the life of the account. I was also instructed to call back in 6 months and they could re-add the 'free family talk for 6 month' promotion. Hope this saves somebody some cash - thanks for reading