Unlike with all other main retailers, Amazon does not allow self publishers to make a book free. You have to set it at the list price and then wait for people to notify them that it is free elsewhere - which they may not know of course - and then they might match the offer at their discretion.
It always happens - of for me it has - but it can ometimes take several days, if not weeks, even with me notifying them every day using the 'notify us of a lower price' option.
So could I ask everyone to help speed things along and notify them. Just click on the book cover there and it will take you to the Amazon page, from which you can use copy and paste any of the links below which are the pages of other retailers where the book is free.
Links to paste are: