I've never paid $15 for a single fiction ebook. There are a small number I might - but they won't sell them to me (some of them are Macmillan) - so if I keep doing what I have been doing this will be easy to do.
In fact, I've checked - have not bought a single book all year, yet. Depending if you count magazine subs as bought in the month they arrive, anyway.
There's a new Selina Rosen bundle at webscriptions, so this may change shortly.