Tripwire Interactive's Killing Floor has a free expansion along with new DLC available on Steam.
It's also on sale this weekend for $9.99, which is 50 percent off.
The expansion is the Incendiary Content Pack which adds the MAC-10 weapon along with four new multiplayer maps and it will not cost you a cent.
DLC comes via the PostMortem Character Pack which includes four new playable characters and normally runs you $1.99, but like the full game itself, it's on sale as well this weekend and will run you $0.99 instead.
That's not all though, because the savings just keep coming for the weekend.
The two previously released DLC expansions are also 50 percent off, and will run you $0.99 each.
Now's the time to get it if you haven't already.