$540 via promo credit when you add a new smartphone line with your own 4G/5G smartphone on postpaid Unlimited Plus plan between 5/18/23 - 5/31/23 & port-in req'd. Promo credit applied over 36 months; promo credits end if eligibility requirements are no longer met.
You would have to call customer support.
I know they did stuff like that in the past.
Given that AT&T bought DirecTv, it wouldn't surprise me to see that go away.