You can always buy them separately when they come out, of course, your first chance to do so being on December 14 when The Adventures of Gunslinger Joe sends you to space. Bethesda revealed the official release calendar for the game's three upcoming DLC episodes - the first, Episode Zero, came out last week - on its official website.
The second pack, The Diaries of Agent Silent Death, releases January 30, and will focus on the exploits of ex-OSS agent Jessica Valiant, an assassin who will fight the Nazi war-machine in California to uncover the secrets of Operation San Andreas.
Episode Zero, introducing the pulp hero cast that will star through the rest of the content, is available now, either as a pre-order bonus or part of the season pass. Lastly, The Amazing Deeds of Captain Wilkins will be releasing in March 2018, following Gerald Wilkins as he makes his way to Alaska to take apart Operation Black Sun.
The Freedom Chronicles season pass costs USA $25 / £18 / AU $35 and includes all of the aforementioned DLC packs. All the DLC can also be purchased separately. You can get all three in the game's $25 Season Pass or buy individually for an as-yet-unannounced per-episode price. Wolfenstein 2: The New Colossus is available now for PC, PlayStation 4, and Xbox One, with a Nintendo Switch launch on the way next year.