Amazon has Halo 4 for Xbox 360 for $39.99 (59.99 – 20 instant savings) with Free Shipping for limited time.

The Master Chief returns to battle an ancient evil bent on vengeance and annihilation. Shipwrecked on a mysterious world, faced with new enemies and deadly technology, the universe will never be the same. Enlist aboard the Infinity to experience Halo’s original multiplayer and Spartan Ops—episodic, fiction-based co-op missions.