Free shipping on Amazon is not just for Prime Members. Since the word "go," Amazon has offered free shipping on orders above a certain size (to encourage those larger and more efficient customers' buying experiences). And that free shipping lives on to this day, though as of now one will have to pay more in order cost to qualify for it.
For many years the free-shipping threshold on Amazon was $25. However, that price went up to $35 as of three years ago. This shipping is not guaranteed in two days, like its Prime-centric equivalent. And now it is also more costly per order ($49 minimum price) to avoid paying a shipping fee (unless one is buying books, in which case the threshold is still $25).
The obvious intention of course is to move more of those holdout to Amazon Prime, with its $99 a year price and unlimited free shipping for there. It also goes a distance to lower Amazon's shipping costs. In the firm's last quarterly earnings report, it was revealed the nation's most successful eCommerce firm was facing fulfillment costs that had gone up 32.8 percent in just a year.