Are we talking about David Weber's
Off Armageddon Reef? I bought that e-book from webscriptions for $18 back when it came out. I did think it over for a while, due to the price, but I finally went for it. My reasoning at the time began with the knowledge that I was going to buy the book -- and sooner rather than later -- so it was a choice between $26 for the hardback and $18 for the e-back. Added to that was the fact that I wanted the e-back more than the hardback (lower weight, greater flexibility, smaller size), and that I could chalk the 'extra' cost (beyond what I consider to be a reasonable e-book price) up to an early reading premium and an encouragement to Tor donation.
The $18 was a bit easier to swallow with those thoughts.
Even after I saw the book in the ConnStore for ~$10 I didn't feel cheated because the copy I had was DRMless, and it's Weber, so I know I
will re-read it for years to come.