I think, not a secret for everything, that variants for editions are now used. 1) the usual edition, rather modest and inexpensive
2) the improved edition, with additional bonuses
3) the collection gift edition, with the BIG HEAP of bonuses.
A classical example - The Lord of The Rings.(DVD)
Why to not publish as the "Sam & Max Surfin' the Highway"?
It would be good both for us and for you - for all! ;)
One request - please, make the book in a firm(hard) cover, because soft quickly wears out from constant use! :D