The Walking Dead is having a sale for today only. Episode 1 is still completely free, but episodes 2 through 5 are 200 ($2.50) each for today on Xbox Live. All five episodes usually cost 400 MS Points each ($5 each), for the entire series would be $25, but today Xbox Live is offering all five episodes for only 800 MS Points ($10). For enthusiast of the comic / TV show now would be the perfect time to buy the series.
Source: The Verge