Steam has the PC version of L.A. Noire on sale for $4.99. The complete edition with DLC included is also on sale for $7.49.
Amazon has L.A. Noire as their Gold Box deal today at $44.99 for Xbox 360 and PS3.
L.A. Noire fans can grab the Rockstar Pass for Xbox Live to get 10 DLC items for just $10. This price is only good until June 14th, and after that it will go up.