This is actually a dilemma I recently dealt with that's kind of jaded me...
Usually, I just hit the "tell the publisher" link and wait, since buying the paper version is a demotivator for their publishing of e-versions.
But recently, I caved. There are a lot of historical fiction books/trilogies I've been dying to read, about the time period and people I'm into, that after 2-5 years are still available in paper-only. So I finally went ahead and ordered the pbook of one, thinking I could then just go to this wondrous darknet to get an ebook copy to actually read. (a Camp Middle-Grounder here.)
Alas, I couldn't find it (or, heck, any historical fiction) down there (at least not in the obvious places I know about), and I was stuck with the paper version.
At first, I wasn't too miffed. I love my paper books, and I probably would have bought the p-trilogy anyway, after being sure I loved the book. But I couldn't half-enjoy reading the book, due to my being under the weather and its being heavy with tiny print.
So now I'll have to scan it and make my own ebook copy. Meh.
What jaded me though, was googling around and seeing some of the authors' and publishers' attitudes toward ebooks, and then adding those to some of the prices of the ones they do have out - ebooks priced higher - up to double the cost of the paper version.
Anyway, before all this, I would have done what I intended - I'm die-hard about making sure authors get paid, especially since the books I like take so much research and effort. But now, I'm feeling so miffed about it, I'm not only refusing to buy the pbooks retail, I've been half-tempted to buy them from Half-Priced books, just out of spite. lol