The Kindle and Netflix apps were free when I downloaded them. The interesting part to me is that Apple apparently insists that providers' external sales prices not undercut the iOS price:
Apple does require that if a publisher chooses to sell a digital subscription separately outside of the app, that same subscription offer must be made available, at the same price or less, to customers who wish to subscribe from within the app. In addition, publishers may no longer provide links in their apps (to a web site, for example) which allow the customer to purchase content or subscriptions outside of the app.
This means that Netflix would either have to take a $3 hit on any $10/mo. subscription initiated from within iOS or raise the price for both the iOS and external subscriptions by a few dollars in order to offset the apple fee.
Not sure how this will play out, but it's interesting. Obviously Netflix and Apple can change their terms at any time. This is a decent opening move by Apple.