If you've ever been in a position where you've bought an app only to have it retired from the iOS App Store and furthermore unsupported as a result of a new paid upgrade, you'll be happy to hear there is a workaround, though it doesn't seem to be a mechanism publicized by Apple.
Marc, Seth, and Rene iterate through Google's Project Glass, upgrade pricing, and Instagram's sale to Facebook, and interrogate Justin Marcucci and Tammy Coron of Nickelfish. This is Iterate!