If you haven't read them already, there's a few classics you should read:
The two or three books of Alice in Wonderland
H. G. Well's The Time Machine
Otherwise, here's a few e-books I've found (with links) that I personally liked (you can skip it if you're not a fan, at all, of sci-fi - because all of them have at LEAST some sci-fi elements, if not being predominantly of the genre):
Starliner, by David Drake. Price at time of posting: Free. Rating: 8/10 - it's a calm and surprisingly mostly uneventful - a huge buildup with a very quick resolution that somehow DIDN'T feel unsatisfactory.
Flying The Storm, by C. S. Arnot. Price at time of posting: Free. Rating: 9/10 a good 'post-apocalyptic' (not really - it's just a really unstable world after a big war, with leftover tech) action-packed story full of morally-dubious decisions. I love it.
Imperfect, by David Adams Price at time of posting: Free. Rating: 10/10 a pretty short story but still an interesting read which made me, at least, wonder about the future of AI.
Lacuna, by David Adams Price at time of posting: Free. Rating: 10/10 The first book of a series that has a (to me, at least) completely new take on the "first contact" premise. As soon as I find the opportunity, I'm buying the rest of the series - that's how much I liked this book.
Black Hull: The First Season by Joseph Turkot Price at time of posting: Free. Rating: 7/10 - a little bit heavy on the "selling" elements like romance and eroticism, but otherwise the premise is pretty interesting. Though it IS just the first six episodes of the series - the first half of the book.
Titans, by Edward W. Robertson Price at time of posting: Free. Rating: 9/10 - I loved the premise, and the execution was to match. There MIGHT be a sequel (there probably is) but this book stands very well alone.
Ghost in the Machine, by C. E. Kilgore Price at time of posting: Free. Rating: 8/10 - I'm not going to lie, the main plot point of this book is a tiny bit of a stretch and probably aimed to sell - yet, somehow, I liked this book because of how it executed that plot point. It's also the first book in a series that I haven't read. Overall, I liked it even though it was at the midpoint between a romance novel, a sci-fi story and erotic literature.
Fatal Boarding, by E. R. Mason Price at time of posting: Free. Rating: 6/10 - a little bit generic, yet there's enough nifty ideas to keep you hooked - even though the biggest plot twist is slightly disappointing. Still a decent read, especially for it's price.
Deep Crossing, by E. R. Mason Price at time of posting: Free. Rating: 7/10 - I admittedly remember relatively little of this book, but I remember it being slightly better than it's predecessor - yeah I forgot to mention, it's a sequel to the book above.
A Memory of Violence, by Percival Arbogast Price at time of posting: Free. Rating: 8/10. Interesting and relatively novel premise, though it's obviously meant to hook you in as it's the first book of a series, and the story itself ends at a cliffhanger. But it definitely succeeds, because it fed me enough information to make me want to buy the rest of the series.
AI Apocalypse, by William Hertling Price at time of posting: $3.05 Rating: 7/10 - the ending was very, very anticlimatic, but the whole story up to that point lead me to think a lot about the future of AI and the precautions and measures we should take to ensure good relationships between us and an AI.
That's all for now. I'll keep you posted if I find more books worth reading.