This is the most straightforward advice. Steam, the Epic Games Store, and other digital retailers hold massive seasonal sales (Summer Sale, Winter Sale, Black Friday) where you can buy the entire Fallout 4 Game of the Year Edition for a fraction of its original price. This edition includes the base game and all major DLC— Automatron , Far Harbor , Nuka-World , Wasteland Workshop , and Vault-Tec Workshop —all legally and permanently yours.
If you don't own the base game yet, this edition includes all DLCs. fallout 4 dlc unlocker