Steam and Origin have some decent offers right now. I've bagged me Bioshock Infinite on Steam (£12.49) and Mass Effect 3 on Origin for £3.99.
There's quite a few good deals on Origin actually and not just download titles but lots of Xbox 360 and PS3 deals too. BF4 is discounted also.
Amazon have also had some games discounted and will do so again tomorrow. And before Timey says it, yeah we know. You're getting a PS4. And you don't care a rats ass about old PC games do ya matey?