Woohoo! Something I actually know about! I self-publish ebooks.
Indie books tend to be the ones you see published for about £1. Of this, the author gets 35% from Kindle (other publishers vary). Approximately 10p of it is for hosting and delivery costs - my books are 'lodged' on Amazon's servers. Amazon also run cusomer services, product support etc. You have to pay towards that. They claim a minimum of 75p of your revenue. If you want to claim 75% royalties, you have to sell at a minimum of £1.50.
If the indie-books are going to have a professional look and feel, you need to get them professionally edited and proofread. This will cost somewhere around £300-£600. Then you ideally want to have a cover designer work on it. Another £150+. So putting your book out there, assuming you do all these things (I don't, but I really use Amazon as a delivery mechanism to get my books to my friends). Then there's advertising. You want people to know your book is out there? That'll cost too.
Assuming your non-time costs are about £750 because you've managed to find all of the elements cheaply, you'll need to sell 2,143 copies at £1 to break even (not charging for your time).
That doesn't sound like much, but in book terms, that's a hell of a lot. That would easily put you into the top ten in the chart. The vast majority of published books out there don't sell more than 100 copies. If you get more than 1000, you're in the elite. Obviously certain books will sell millions, but they are by a long way in the minority. If you get lucky enough to have your book featured in national media, you can look at 100,000+. But even books from publishing houses don't often manage that.
You'll sell most if you're able to get your book on a 3 for 2 table in a major retailer. Publishing houses will make a loss on books they place there. They're aiming for increasing the ciculation footprint. That option doesn't exist for eBooks. There's some browsing, some downloading of sample chapters, but there isn't much impulse buying. Some, yes, but not masses.
And then there's your time. The books I write are short - 100,000-125,000 words. And they're fairly light-weight. It took about 18 months to get my last book ready for publication from typing the first word, to uploading it. All of the work I did myself, with the exception of getting someone else to do one of the proof readings. Hours wise, it's a lot of time.
I will not make money from my book. I don't mind; I do it for pleasure, but if writing is your only form of income, you can see how many copies you would have to sell to recoup that time!
So I can totally see why people sell at a rate that will make them, say £1 per copy rather than 35p.
The final point is that the publishing houses set the prices for their books - not the author. They will inevitably set the prices to be either the same as the print copy, or for just a pound or two less. It will also (usually) come out a couple of weeks later than the print copy. I honestly can't tell you why this is as I'm not involved in that part of the industry, but I assume there's an industry advantage for print sales.
Final comment on VAT - VAT on eBooks is set at 3% (I know, us writer's don't know we're born). I'm just mentioning this as it doesn't effect the price as much as you'd suspect. I try to absorb the VAT - so I set the price lower so that you'll still pay 99p for the book, rather than £1.03, and I take less royalties.
In short, like someone said upthread - the price isn't just the paper and ink - it's all the 'thinking' that goes into it, and not all of that is just the author's talent.