For the latest Origin giveaway you require Amazon Prime and it's free Amazon Prime gaming *used to be called Twitch Gaming). If you have Amazon Prime you can get Battlefield V for free until September 1st.
You should find the deal HERE. I've used my logged in account page so it may not work. If it doesn't you can get to the appropriate page via Shareware on Sale HERE
You can read an excellent review of the game via Rock Paper Shotgun, written by Mat Cox HERE and see a few videos of single player and multiplayer campaigns HERE (SP), HERE (SP), HERE (Coop), HERE (MP), HERE Beginners Guide to modes, menus and servers).
I think Battlefield 1 the WWI scenario is also free via Amazon Prime Gaming?
