Here is AT&T promo to follow suit with T-Mobile and Sprint, except no trade-in. Looks like existing AT&T customers not eligible since port required. Existing DirecTV customers are eligible.
Switch and get a FREE iPhone 7 (32GB) when you have DIRECTV.*
*When you buy on AT&T Next® with qual. wireless svc. (min. $50/mo.) and TV svc. (min $29.99/mo.).Free after $650 in monthly bill credits. Tax due at sale. Ltd-time offer (Ends 9/30/16 in PR). Priced $650. Req's port, well-qual. credit, and 0% APR 30-mo. $21.67/mo. agmt. Up to 3 mo. due before credits start. If svc. canceled, device balance is due. Must maintain both svcs for up to 30 mos. Activ., other charges & restr. apply. Void in CT, RI & Miami-Dade.