You can get the Fallout 4 DLC for free

When Bethesda further detailed their plans and pricing structure for Fallout 4's upcoming DLC, they also revealed that they will be running closed betas for the DLC on both consoles and PC. Any gamer interested in testing the upcoming content can sign up to join the DLC closed beta, with a special bonus.

If Bethesda selects you to participate in the DLC's closed beta testing, you will receive all of the game's DLC as thank you.

If you choose to sign up for the beta, there's something you should know. Written in DLC Beta Agreement, that you must agree to in order to participate in the beta, is a Nondisclosure section (which you should familiarize yourself with) and a note that the developers can reset your game at any time during the beta.

ZeniMax reserves the right to reset the Game, Your Game account (if any), Your characters, inventory items, achievements, and/or in-Game settings at any time during the Beta Trial.

During the course of the Beta Trial, regular and unscheduled wipes of player progression (which may include characters, character names, guild names and/or other personas) and/or saved games (which may include inventory) may occur at any time, at the sole discretion of ZeniMax. ZeniMax makes no guarantees about the persistence or availability of player progression or inventory items at any time during the Beta Trial and assumes no liability for lost or deleted account data, including character data

These resets can effect your entire account or simply remove items from your inventory. You can sign up for a chance to participate in the beta here.