Hitman: Absolution is only $4.99 on Amazon right now.
GTA 4 is $9.99.
BF3 is $18.61. I like that game. Obviously awesome multiplayer but a surprisingly good campaign as well.
L.A. Noire is $14.99
Also Max Payne 3, Mass Effect 3, Kingdoms of Amalur, Just Cause 2, Dead Island GOTY, Borderlands GOTY, The Walking Dead, Alice: Madness Returns, Deus Ex: HR, Assassin's Creed: Brotherhood, Amnesia. There are a ton of great games at or under $25...you just have to look.