Death Star DLC Price
If you're looking to buy the Death Star DLC as a standalone add-on you'll need to fork over $15 for the rights to the content.
Death Star DLC listings at GameStop and Amazon confirm the $15 standalone price point and that'll be the DLC's standlone price at other retailers in the United States. International pricing will vary.
If you opt for the Star Wars Battlefront Season Pass, be prepared to fork over $40+. Again, it comes with all four DLC's including the last DLC which is set for release sometime in December.