I'm surprised no one has mentioned this yet, but A Charlie Brown Christmas by Loud Crow Interactive Inc. has had a big price drop. App info is currently processing and/or the app is not yet fully available for sale on the US App Store. The in-app purchases for this book are completely optional decorations for a tree that is then featured in the book should you choose that option. The in-app purchase of additional content has been made free.
This app's price has been further reduced to 99 cents this morning! For that price, it's an instabuy imho. Great book and very nicely implemented (even if it does crash a lot on my 4th gen iPod Touch).