I have been using BookBarista to advertise our books for some time now. I originally found out about them from a Tweet I saw recommending them on Twitter. One of the things I like about advertising on their site is that you receive an email from them the day before your advert is due to expire, reminding you to renew your advert, but they also include in the email a really useful link to click on and follow to take you straight to your book’s page, which saves you having to log in and looking for the correct webpage.
Their about me on their website says that they are “a site dedicated to books, eBooks and reading! It doesn’t matter if you are a reader, a self-published author, a popular, commercial author, or someone offering a book related service. BookBarista is the place to advertise your book related items, new or used, that may be for sale or for free. We also have a BLOG where site users can get news and updates about what’s going on here or there in the big, competitive writing world.”
I highly recommend checking them out 🙂
Their website is http://www.bookbarista.com/