Probably the cheapest these two great new Telltale games have been yet:
The Walking Dead: Season 2 (PC/Mac) @ US $8.74
The Wolf Among Us (PC/Mac) @ US $6.24
Telltale account required for game activation and installation. When activated, you can choose to download the PC or Mac version.
Not available on Steam.
The Walking Dead is also 75% off @ US $6.24