https://www.cnet.com/news/amazon-extends-free-shipping-offer-to-items-purchased-by-dec-18/

Prime is one of the company's most important businesses, helping build loyal, repeat customers who tend to spend about twice as much with Amazon as do non-Prime shoppers. 

Amazon Prime subscribers, who pay $119 for perks such as free shipping and access to music, movies and TV shows, purchased more than 2 billion items on the site with one-day or faster delivery, the internet retailer said earlier this month.