There’s no mention as to how long the sale will last, except for that it’s a limited-time offer.
The Kindle Fire HDX 7″ Tablets can be used for apps, games, books, movies, magazines, music, web browsing, and more, all on an 7″ HDX display (1920×1200), high pixel density (323 PPI) high definition display. Choose from 16 MB, 32 MB, and 64 MB models, with or without special offer ads, and Wi-Fi only or Wi-Fi and 4G.
— You can gift Kindle books and set your gift to be delivered whenever you want to anyone with an email address. On the Product Page (on the top right side), click the button that reads “Give as a Gift.” From there you enter the recipient’s email address and note the date you’d like your gift to be delivered via email, and also include a personalized message. There’s also the option to have the gift emailed right to you that you can forward the gift email to the recipient yourself or print it out and personally deliver it to the recipient.
— You don’t actually need a Kindle device to read these ebooks. Books can be read on a Kindle or one of Amazon’s free reading apps for iPhone, iPad, Android, Windows PC, Mac, Blackberry, and Windows Phone 7.