If a hardcover book costs $100, it is most likely some high-quality scientific book that was never printed in great volume. I would pay that price because there was no alternative and MANY people recommended it to me.
For ebooks however, there is no such thing as low-volume hardcover prints. Unless you write the very best book on this whole planet, I would not be able to justify shelling out $100 for an ebook.
$100 is the price you pay for Microsoft Office or Microsoft Windows, because there is no alternative and it took hundreds of people several years to build it. $100 is the price you pay for two brand-new blockbuster video games that both took hundreds of people dozens of months to make. $100 is not the price to pay for what one writer has done in a year or so. At least not to me, I'm sorry.