Respawn Entertainment's David Wightman confirmed to Gamesradar that all future Titanfall 2 maps and modes DLC will be free.
"We'll definitely be supporting Titanfall 2 post-launch, and I can confirm all maps and modes we deliver post-launch will be free. We'll be talking more about post-launch plans closer to release so stay tuned for more info."

Wightman did go on to explain that they also won't sell any "pay-to-win stuff." However, he did not actually specify what they would be selling. I'm assuming it's going to be a lot of cosmetic stuff for your characters, weapons, and Titans.

In case you missed it, be sure to check out the E3 2016 trailers for the Titanfall 2 single player and the Titanfall 2 multiplayer.