Can I purchase DLC if I claimed the base game for free in the Epic Games Store?

If you claimed a base game for free on the Epic Games Store, you don't need to purchase it to get the DLC as it's already in your library. You can purchase the DLC without any issues by following these steps: 

1. Open the Epic Games Launcher
2. Find the game in the Epic Games Library
3. Click the three dots next to the title
4. Click Explore Addons
5. Choose the DLC you would like to purchase