I have a couple of books published free and name your own price on Smashwords, but they do an annual sale where books are discounted for a month or free. You can look them up by category, but as authors have to apply, you may find new additions to the list daily. Please Log In to view this link!
I have published books on Amazon Kindle and Amazon createspace. I knew smashwords ebook publishing platform before I knew about Amazon publishing platform. However, when I was ready to publish books, I chose Amazon. I chose Amazon because it is the largest online publisher and retailer.I have smashwords account, I will check your books. I may even land up buying few.
It's a good way to promote books for a month, and you can easily publish on Smashwords as well as Amazon. My books are on both platforms, but I don't market them heavily as they are more memoirs. The good thing about Smashwords is that you can offer coupons and promotions unlike Amazon, and it's good for SEO.