A few more cheap-ish games and bundles:
2 awesome real-time with pause RPGs, inspired by the Gold and Silver age of comics.
I still consider this series to be the best thing Irrational Games ever did:
Includes 2 items: Freedom Force, Freedom Force vs. the Third Reich
store.steampowered.com
3 games + 1 expansion; the last game was developed by Obsidian, and despite the underwhelming reviews, I found the game to be very enjoyable to play with a controller:
Includes 4 items: Dungeon Siege, Dungeon Siege II, Dungeon Siege III, Dungeon Siege III: Treasures of the Sun
store.steampowered.com
Do you like pirates, and can tolerate some "jank" in your games?
Look no further, this is the game for you:
One of the best puzzle-platformers available on Steam. Certainly the best one featuring a goat, who's escaping, while having a "2" in the title.
I may be biased, because I helped test the game, and my name appears in the credits.
There are plenty of great shmups on Steam. This is one of them. Also, probably the bluest:
What? You want a shmup with more anime girls and less blue?
Here's one: