Right this very moment, Amazon is running a «Digital Day» sale. The site says it has up to 80% off on all sorts of digital goods, starting with games but also including movies, music, and applications. There are reduced-price items in nearly every type of thing the site sells in digital form, so it’s definitely worth a look.
In PC gaming alone, there are big deals to be had, including Cities: Skylines for $7.49, Bioshock Infinite for $6, and either Tomb Raider 2013 or Saints Row IV: Game of the Century Edition for a measly $5.