We now have in app purchases for free apps (read: trial ware).
It’s not quite perfect, as I am sure most developers would like to allow full functionality to users for a timed duration. (Maybe this will be allowed?)
From a consumer side, I hope this isn’t abused to much.
I have a strong feeling that we will see much more of a lash back if users of free apps are constantly bombarded to make in-app purchases.