Originality is key for me, if I even have a slight feeling ive heard of it or read it before, it massively reduces the chance of me purchasing it.
The creator also has to be able to show some form of intelligence when questioned, and dealing with sales. Any rudeness, or severe lack of spelling/grammar, again, puts me right off.
Before buying an ebook, I usually check how the thread is made, as in, professional looking or not. At most times, I can sense if an ebook sale/thread is a scam. If I feel there is not enough information, I ask.
Check the seller's reputation and the ebook's official reviews if needed, and also if the ebook sounds or is unique.
Over all it's the aspect that I can learn something new.
What really makes me read it? When I look at the review and I see good quality and grammar.
But if the ebook reviewer did a bad job I wouldn't buy it because it makes me thing they had to make run off sentences so they could complete the review.
Good vouches and or knowing the member increases my want to buy it.
What makes me buy an eBook is originality and ease of use. Because if something isn't original or easy to use, then what is the point of buying/using the eBook?
Well, first off I see if it's something a kid made in 10 minutes or if it's something somebody spent a lot of time on making and is actually aiming to help people.
Secondly, I look at how professional the thread is; if it looks good and detailed then that's another factor I take into action.
Thirdly, I look at the official reviews, official reviews are always something you should incorporate.
Fourthly, I look at the user's reputation, if he/she has any negative reputation that was about scamming, or something serious, then I wouldn't deal with them. I also wouldn't deal with them unless they have at least two people how +repped them.
Fifthly, I look at how trusted the user is.
Well that's basically how I choose whether to buy an eBook or not; but nowadays I never buy eBooks because I already have working methods that I created !