So Steam just hates money at some point, and they just decide to cut the cost of a lot of things at a whim, and they are having a summer sale, and some of these deals are insane
Such as this one:
http://store.steampowered.com/sub/4583/
Or this one:
http://store.steampowered.com/sub/440/
This is a bit different, but I hear its like TF 2 in the Old-West, though guess got RDR for that now
http://store.steampowered.com/app/42120/
The Nerd Pack
http://store.steampowered.com/sub/4593/
http://store.steampowered.com/sub/683/