In some ways, my books are like my children. I decided I was spending too much time on my Amazon offspring and not giving enough attention to their other-platform siblings. Ergo, I made The Sixth Disciple free on Smashwords. The new "price" takes effect right away on Smashwords but it can takes days or weeks for the change to filter out to their affiliated retail sites.
I'll monitor the other platforms and report when TSD shows up as free on any of them. It will be interesting to see what happens on Blio. I don't know if they allow authors to make books free or not. I guess we'll find out!