Amazon to discount Prime from $99 to $79 on Friday

The one day 20-percent discount comes just in time for Black Friday.

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(Image: CNET/CBS Interactive)

Amazon is discounting Prime from $99 to $79 in a rare, one day sale on Friday, Nov. 18.

New Prime users will gain access to free two-day shipping on a vast amount of products sold on Amazon.

It's estimated there are more than 60 million Prime subscribers. The service also offers access to a library of movies and TV shows, ad-free music, unlimited photo storage, and Kindle books.

The discount is being offered to celebrate the launch of its new Prime-only TV show, The Grand Tour. If you've been thinking about signing up for Prime -- Friday is the day.

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