This section can be accessed in the Play Store on the web or on mobile. All you have to do is go to the main page of the Play Store and scroll down and you will find a “Free App of the Week” section. Of course there are more free apps or discounted apps than just the one that is being shown, so in reality this section just points out to users what apps that they can check out.
As it stands the free app will is “Card Wars – Adventure Time” which is ending in a few days. The price of the game is normally set at $2.99 but it will be free for the next few days. So if you do like a good deal every now and then, you can check out this particular section to see what is new. There is no guarantee that the app displayed will be useful for you or what you wanted, but free is free, right?