Here is an example of one of the books I have in paper form and that I refer to often for work
http://www.amazon.com/Operational-Qu...607325&sr=1-40
The difference between the Kindle and the paper version is around $30, assuming the paper version is brand new. However, you can obtain a paper copy in very good condition (used) for a very low price. This is what I am referring to. What is the motivation to buy the Kindle version from a financial perspective?