How low can you go?

As someone that will be publishing an eBook next year, I am super curious about how people decide to price their books.
When I look for a new book to read, the cost is certainly a factor. It it’s too expensive, I’ll wait for it to go on sale. On the other end of that spectrum, if a book is free I may be less apt to read it, unless it has a whole bunch of great reviews (did they get those by giving the book away?) If you have published a book I would love some insight on what you sold your book for, and why!