They Shall Not Pass Price
At this point, DICE hasn't confirmed a specific price for the standalone version of the They Shall Not Pass DLC though it's quite easy to predict ahead of launch.
We expect They Shall Not Pass to command $15 as a standalone piece of DLC content. This is standard practice for EA and it's the formula the company's used for previous DICE titles including Star Wars Battlefront.
So what this means is that you can expect the Battlefield 1 Premium Pass to be a bit of a deal on the DLC expansions.
The Premium Pass is $50 without a deal which means you'll likely save $10 on all upcoming expansion packs for Battlefield 1.
Don't expect to see a ton of They Shall Not Pass deals for Xbox One, PlayStation 4 or Windows PC.
While we could see a few retailers (GameStop or Amazon) offer a deal on the standalone piece of content, we don't expect to see any deals emerge right before or right after the DLC's release in March. It would be a major surprise if something emerged.
If you don't want to pay the full price for the DLC expansion you'll likely have to wait. We could see a few deals emerge over the course of 2017 though we wouldn't expect any blowout deals on a $15 expansion pack. (Note that we haven't seen many for Star Wars Battlefront.)
You're more likely to see retailers (and EA) offer deals on the Battlefield 1 Premium Pass. We've already seen the price drop by $10 at some places so you'll want to keep an eye out for Premium Pass deals.