AT&T deal NOT thru Costco -Buy one iPhone 8, get iPhone 8 free, at least one new line required.
iPhone 8 bogo at att store. This is different from the other deal and I didn't see the info posted in there. You can do the same deal but you don't have to pony up for an X and you can get the phones immediately. It's a 700 dollar credit and requires a new line and activation.
No direct tv necessary either.
Note: if you preordered an X from Apple you'll not be eligible for to use the x bogo even if it was an upgrade. This is assuming full payment for the X. I don't know if they're do it with the next plan.