Hi. It is apparent to me that you have designed your site to be scalable for when you have a much larger number of books available, so some of my comments may not apply once your reach that state. But here goes.
Starting with your home page clicking on any of the four current choices for ebook categories (for kids, popular fiction, adult fiction, non-Fiction) presents the same list of books. What is the point of having these buttons since that is the case?
The check box to filter out public domain titles does not work. Checking it than conducting a search still returns mainly public domain titles when searching General Fiction Adventure sorted by price; almost all the titles listed are are public domain.
I don't care for the in page scroll box presentation of longer text, but that's just my preference.
Still it has the potential to be a great resource.