I'm bummed I can't use this myself since I already have an account, but I know there are several self-published authors on these forums. I noticed today that the Amazon Marketing Services portal is advertising "$100 in free clicks*" with the asterisk referencing terms at the bottom of the page:
https://ams.amazon.com/Terms include that the promo is for new accounts opened between Jan 1 and March 31, 2017. AMS is a portal for setting up and bidding on pay-per-click ads to promote your goods on Amazon.com (and only .com right now, at least for books).
