If the Girly book collection is $100 and I already have the first two books you released and you have a milkshake and I can't really justify buying things if I already own $50 worth of it and I have a milkshake and my straw starts reaching across the room,

Correction! The original printings of the first two books are entirely included in the first of the four books in the set (hence the title "Book I & II" and all in all comprise about 20% of the material in Girly.

That being said, those who already bought the original printings, I'll think of something to do for them, such as the option to include a free sketch or something along those lines.