We love a good App Store pricing story, and this one has a happy ending (mostly). Yesterday Wired picked up the scent of Autriv's SignMyPad Pro, which has a rather breathtaking price tag of $99. Since the non-pro version of the PDF-signing app -- which shares almost all its features -- is only $4, why should the Pro version cost more than 20x as much? Not to mention that the PDF signing genre on the iPad, while not as crowded as some other sectors,
