Get ready for super-fun Amazon Prime Day! Prime Day is the biggest online shopping day of the summer! Last year, according to Market Track and Qualtrics, about 30% of US internet users participating in the Amazon Prime Day sale. The web site eMarketer expects this year’s Prime Day to surpass out last year because of the surge of Amazon Prime memberships, which grew from 50.8 million in 2015 to 67.7 million so far this year. Amazon Prime customers, are nearly half of its U.S. customer base. Prime customers spend, on average $1,200 on Amazon compared to non-Prime customers who spend approxiamately $700.