Is selling eBooks profitable?

It's possible. There are a few measures that can help you make money selling eBooks.

Make your book the best it can be, and make sure it's directed at a market that'll buy it. Invest in a professional editor and proofreader. Pay attention to what your editor says and make the adjustments they suggest. Make sure the genre you're in is represented on your cover. The purpose of the cover is to entice the reader and hint at what they will discover within.

Make sure your blurb is short, starts with your primary character, and doesn't attempt to convey the entire plot. Write a sequence of stories. Don't try to promote your books until you have at least three. At five, things start to get simpler again. It doesn't matter how many more you write after that as long as the quality stays good.

Set reasonable pricing for your product. Do not be concerned about book reviews. You won't have any at first. Any service that promises to earn you reviews should be avoided at all costs.