Amazon is about to turn 20, and to celebrate its two decades, the retailer is hosting a special sale for Prime subscribers.

From just after midnight PDT on July 15, eligible customers will be invited to a one-day sale the company is touting as “bigger than Black Friday.” There will be no restrictions on how long customers need to have been Prime subscribers, meaning non-subscribers can sign up for a 30-day free trial just to get the deals.

“Members tell us every day how much they love Prime, and we will keep making it better,” said Greg Greeley, vice president of Amazon Prime, in a statement. “If you’re not already a Prime member, you’ll want to join so you don’t miss out on one of the biggest deals extravaganzas in the world.”

It’s been almost 20 years since Amazon first started selling books to customers through its website. The first book sold was "Fluid Concepts & Creative Analogies: Computer Models of the Fundamental Mechanisms of Thought." One month after launch, the company had already made a sale in every U.S. state.  In "The Everything Store," a book about Amazon’s early history, author Brad Stone revealed that the company used to hold meetings in a Seattle Barnes & Noble. Back then, the company consisted of three people. Original employees were expected to work 60 hours a week minimum.

The early days were tough. An SEC filing from March 1997 showed that Amazon had a deficit of $6 million in December 1996, and was expecting to incur operating losses “for the foreseeable future.” In January 2002, nearly seven years after its first sale, Amazon announced its first quarterly profit. On the 18th of that month, Amazon shares were worth $10.16. At the time of writing they are now priced $437.71.