Via the Robert Ambrogi's Law Sites, the currently most expensive iPhone application (at $999.99) is the complete California Bar Exam Preparation available via an iPhone Application.
The app is over 1 gigabyte in size, which is the largest application I’ve ever seen. It includes thousands of pages of materials as well as hundreds of hours of audio lectures. It’s all the information you could ever want for the two-month course. And again, it can be done all on your iPhone. That said, if you do want some more tangible paperwork for certain sections, BarMax will send you that electronically as well. ~ TechCrunch