-Red Steel is usually $29.99 everywhere. It has it's problems but I found it very enjoyable. It starts off pretty bad between the graphics, learning curve and rushed coding of the game but gets better within a couple of hours.
-Elebits is fun and I think I've seen it at some places for $39.99 but it's still a $50 title.
-Far Cry is $19.99 everywhere but I've read that it is HORRIBLE visually and gameplay wise (haven't played it myself though).
-Call of Duty 3 I have heard some great things about the controls. That it has the best FPS controls next to the unreleased MP3:Corruption. That title is usually reduced as well (around $30-40).
-The Godfather Blackhand Edition has received great reviews but is still a $50 title (I'm buying that once I see a decent deal).
-Scarface got even better reviews than Godfather but I can't remember if it's been released or not (I think it has). That title is full price as well ($50).
-Also there is RE4 which isn't exactly a shooter like you may be looking for but there is a lot of shooting involved and it's only $29.99. That is if you haven't played it before.
-Lastly Metroid Prime 3 Corruption comes out August 27th and is supposed to be the mother

ing bomb.
Good luck and let us know what you get!