Apple is taking a few pointers from the Amazon App Store and Google Play, by offering its "Editor's Choice" and free app of the week in its Mac and iOS app stores.
The Verge says it's the first of its new "editor's choice" branding -- and it's being used to promote Cobook, a new contact manager, as well as Facebook Camera and Sketchbook Ink. However, the free app of the week is definitely a takeaway from Amazon's App Store (perhaps Apple feels it's owed something especially since it's suing Amazon over the use of the name Appstore something it's trying to trademark.)
The only difference is that while the Amazon Appstore frequently offer apps gratis or at huge discount, promotional pricing for iOS and Mac apps is usually left to the developer or publisher who sets the price. It's likely that the free app of the week is a promotional idea that developers either embrace or don't use -- depending on whether or not they believe a free version promotes users buying the paid version.