In order to get Borderlands: The Handsome Collection for FREE and keep it forever, you need to:
- Login to Epic Games Store
- Visit Borderlands: The Handsome Collection store page, press "FREE" button and confirm your order
The Handome Collection includes Borderlands 2, Borderlands: The Pre-Sequel, all additional content released for the games.
The next freebie game is a mystery, but according to rumour it might be ARK Survival Evolved. Enjoy!