You can get five free digital Black Panther comics this week:
https://www.polygon.com/deals/2019/2/6/18214013/black-panther-comics-free-black-history-month-marvel
In short, you’ll need a Marvel account (doesn’t need to be Insider), visit Marvel Redeem | Marvel, and use the code “FOREVER”. If you’ve linked your Marvel account to Comixology, the comics should unlock there too.