This giveaway is intended to help authors gain new subscribers. You must have a mailing list to participate, and you must share the giveaway to your mailing list during the week of the promo, in addition to any social media platforms you use. Failure to do so will mean you won't be able to participate in future promos.
For those in KDP Select, make sure you are only offering a sample up to 10% (appropriately labelled as a sample) to avoid violating Amazon's T&Cs. Your book only has to be free on Instafreebie.
Your giveaway should be active for the entire month, not just the "official" promo dates. The page is assembled at the beginning of the month and gets traffic right through to the end of the month, so you will gain subscribers on either side of the official promo week.
Giveaway will be hosted here: http://sffbookbonanza.com/freebooks/
For more info, and future promos, see: https://www.facebook.com/groups/instafreebiepromos/
If you haven't already signed up to Instafreebie, do so here: https://www.instafreebie.com?invite_code=exGkmiVfUP
I am also running an accompanying SFF 99c Promo, where we can offer readers some additional bargain books. You can apply for that here: https://goo.gl/forms/eo5wfqqeaqlZ6kyq1
For more Sci-Fi and Fantasy promos, join the SFF Book Bonanza group: https://www.facebook.com/groups/sffpromos/