Earlier this year, the price of a #1 New York Times bestseller, The Silent Patient, was slashed from $12.99 to $2.99 for one day only.

And other huge books were discounted to $1.99: titles like The Maid, A Court of Thorns and Roses, and Killers of the Flower Moon. Colleen Hoover’s Verity was discounted to $3. The Da Vinci Code was given away for free. In all of these cases, the discounts were only available for the ebook.

Most people were completely unaware of these deals.

A select group of readers, however, had the inside scoop. They were using BookBub: a daily email that alerts readers to free and deeply discounted ebooks that are available for a limited time.

More than 15 million people have signed up for BookBub’s free service. You sign up with just an email address, and answer a few questions about what you like to read. Each day, you receive an email with personalized ebook deals, from the biggest books to hidden gems.

Then you buy from your favorite ebook store, and read on any Kindle, tablet, phone, or other device. The ebooks are yours to own forever.

From romance to mystery, thrillers to nonfiction, and literary to historical fiction, there are more than 40 categories to choose from to customize your email.

Each title is handpicked by BookBub’s team to ensure the highest quality — they do the work for you. BookBub partners with thousands of the industry’s leading publishers and authors to find the best deals. Each book is up to 95% off, and many are free.

The New York Times calls it “bargain-basement deals on ebooks.”

And readers have become practically obsessed with the service. In many cases, they’ve downloaded hundreds of books and saved hundreds of dollars per year.

“I now have more books than I can read in a lifetime,” said Suzie Miller of Auburn, WA. She said she has downloaded more than 350 free ebooks using BookBub. For millions of readers, it’s the secret to saving money on ebooks.

P.S. Each deal is only available for a limited time. To see today’s deals, sign up for free.