Steam cuts up to 75% off a different selection of downloadable games for Windows and Mac each day during its Autumn Sale. With prices starting at $3.74, several titles are at the lowest prices we could find. Deal ends November 27. Some best bets:

• Orcs Must Die! for PC for $3.74
• Duke Nukem Forever for PC and Mac for $6.79
• Portal 2 for PC and Mac (pictured) for $10.19
• Call of Duty: Black Ops for PC for $29.99
• browse all of the Steam Autumn Sale