Pretty please buy it direct from PragProg. You get the Kindle version and the PDF (and an ePub) that way. Plus, I get more royalties. :)
Equivalent to saying: "Please give me more money... because that way i get more money"
If he/she doesn't like amazon's price... then don't sell on amazon.
Any sale is better than no sale.
But yes, I get more money because there's no Amazon middleman. Even if it was the same price on Amazon, I'd get less royalties.
Just being honest.
If you push an update, I can buy that as well on amazon (and still only spend $14.40 total)...
EDIT:
1/3rd of the product? do you mean there is only 1/3rd of the book? or are you referring to the formats? That is an odd way to describe the product. I would say the product is your knowledge, not the paper/format it is produced in.
It would be so easy to implement that for arbitrary books, but even Amazon probably has to add a bit of vendor lock-in here and then.
I wish Manning would do that for their MEAPs.