Smashwords has over 1 million readers that purchase books on Smashwords. In July every year they have a Summer/Winter sale, which Smashwords promotes. Special pages if the reader clicks the Summer/Winter button on the first page. The reader has same search of genre & price ranges and looks at all the books on sale.
So, the readers know whatever the price of the books were (and they can see the price) they enter the coupon codes and get the discounted price during July. Everyone is happy. I hope I get some reviews from the readers when they finish reading my books. Most don't review on SW, but some review on Goodreads.
And in the back of my books I have a link to my blogs and email newsletter list for them to join if they liked my story. If the price is less than .99c it is set to Free automatically otherwise the sale percent is deducted when the reader purchases.
You can still enter your books even though it has already started by clicking the Author Sale link on the home page (in the left column I think).