The Sniper Elite: Nazi Zombie Army 4-Pack is on sale for $44.97 (25% off) today at GMG. It stacks with their 20% off voucher GMG20-P4DLK-FKYRS, which drops th price to $35.98.
That’s about $9 per copy. This game uses Steamworks, so Steam activation is required. This is good if you didn’t get in when Amazon had their price mistake on the four pack.
They had the same price mistake twice actually, and I missed it both times =/