Cheap game deals are one thing, but free PC games are even better. GOG are currently giving Little Big Adventure away for free over the next 24 hours to celebrate a brand new French language storefront and French game sale! All you need to do is log in, scroll down to mid-way down the front page and click the banner. At which point you get your free PC game immediately.
It's also worth checking out the new sale, which contains some nice retro bargains. I'd personally recommend underrated strategic RPG Aarklash Legacy for £3.79 (an £11 saving!), but Indigo Prophecy and Another World are also very cheap indeed.
Thanks and credit to jaystan @ HUKD, who individually brought the freebie and the sale to the internet's attention!