If an ebook costs less than $5 (or maybe $6), I just buy it. If a books costs more, I either wait until I can find it discounted or check if I can get the book in good state secondhand much cheaper. And I usually can.
I have a lot of paper books and the longer it takes for the ebook sellers to lower their prices the more sales they miss.
Jorgen
http://cebooks.blogspot.com/