Google debuts the "Free App of the Week"8
We really don't know if this is something that is going to be a regular feature of the Family section or if Google will switch between other categories. Best thing to do is to check in again next Friday and see which app Google is giving away.
Have a particular paid app that you have been looking to buy from the Google Play Store, but for one reason or another you haven't yet pulled the trigger? While life rarely works out this way, perhaps you'll luck out and the app you want will end up as the free app for one week.
source: GooglePlay via AndroidandMe