You can play the realistic military simulator Arma 3 for free this weekend on Steam and also buy it for $30, a 50 percent discount.

The game is free to play now through Sunday at 1 p.m. Pacific Time, and the 50 percent discount offer will end on Monday 10 a.m. Pacific Time.

Players can also log into Arma’s website with their Steam account during the free weekend to vote for their favorite Arma 3 mods and maps in the €500,000 Make Arma Not War contest, a collaboration between developer Bohemia Interactive and the International Committee of the Red Cross (ICRC).

The winner of the Total Modification category (DayZ, for example, is an Arma total modification) will take home €200,000, while in the other categories the prize money is divided between first place (€50,000), second place (€30,000), and third place (€20,000) winners. You can vote in the contest until October 31, and the winners will be announced on March 5, 2015.

Steam has a few other great deals this weekend. You can get Saints Row IV for $6.79, Metro: Last Light Redux for $15, Dead Island Riptide for $5, and Risen 3: Titan Lords for $33.49.