It seems like the coupon option might be a good way to give a book as a giveaway, either for signing up to an email list or in an actual giveaway. (indiesunlimited.com)
Use it to help you craft the perfect landing page for your lead magnet offer, and get the most visitors signed up to your email list. (hacktheentrepreneur.com)
I have signed up to your email list using two of my email addresses now but I still haven't received a link to confirm subscription from either. (deliciouslyella.com)