I just wanted to refloat the 1st post by DiapDealer (i always read Diaper in your name
).
You are paying for what the product costs (the words, creativity?); the paper, the hard covers, the little front photo its just means to an end.
The fact that there is different media to get it, doesn't means you are entitled to get the other media formats for free (silly you!).
But, as has been brought on the topic, it would be amazing to be able to have a package discount for purchasing hard+digital format copies.
Complete economic offtopic:
An economic transaction takes place when someone is willing to exchange his product for the right price, while the buyer is willing to exchange X amount of money (product satisfaction) for the product.