400 Days acts as an inbetween episode for Seasons 1 and 2 of Telltale's The Walking Dead series and can now be picked up for only 82p/$1.24 from this site. It's a Mac store download, but it's also PC compatible.
While 400 Days doesn't star characters from the main series, it plays a minor part in Season 2, so be sure to hook it up with an existing save from S1. This is a super price and should be snapped up immediately if you're yet to play Season 2.
Thanks to jaystan.