I just printed out 5 books on two reams of paper ($3 each) and a $23 ink cartridge; the books were about $7 less as PDF... 5x7=$35... and I spent $29 on the paper. (I am printing them out half-sized, as well... and sleeving them...$3 for 60 sleeves.) and still have a cartridge and most of a ream left.
I could have printed full size and still saved.
So I'm able to reduce the size, and make it both more flexible and more durable. Works for me.
I do wish the PDF's were just a touch cheaper, and that typo/errata correction uploads were made.
More over, I can search, extract, and otherwise make easier use of the PDF's. In the long run, it's a better deal, but just barely at the current price.