I've got a short story collection up which I've had limited success with so far, but my real throw of the dice is the novel I'm planning to put up by April (I hope..!)
This book is pretty decent - I almost got an agent for it - but it's long - currently 160,000 words. It's finished but what I'm doing now is expanding it and tightening the characters and the writing on the advice of a couple of beta readers. I wrote it pretty threadbare originally so it's likely to go up in size by 10 or maybe even 20,000 words if I add in a few more chapters. It is a single novel with room for a sequel (I've started one) but it splits neatly into three parts within the current story. I want to give value for money but I'm wondering if it would be better to offer up the first part (currently 56,000 words) as a teaser at perhaps .99c a few weeks before the full book gets released, or even to split it into a mini-trilogy with each part priced quite cheaply. If I was going through a traditional publisher I would obviously offer it as a single book but epublishing has changed the state of play somewhat and I want to maximize my sales potential. I just don't want to irritate anyone.
Ms Ito's Bird & Other Stories now available
Going Underground (a teaser story) now free
If your book genuinely splits into three - and they work as standalone books - then I'd go for that option. As you're going through a large rewrite, then I assume you'll be able to tighten up the endings too.
Having more than one book is a great asset when you're trying to build a fan base and makes marketing a lot easier.
However, if it's really just a single book, and readers will end it a little unsatisfied and feeling resentful that they have to pay extra to know what happens, rather than satisfied, but wanting to know what happens next, then I think that might disappoint a few people.
You want to sell books, but you also want people to become fans of your work.