Amazon isn't the only retailer celebrating Amazon Prime Day

Call it a glorified ad campaign. Call it whatever you want, but Amazon's third annual Prime Day is here. Amazon introduced its first Prime Day in 2015 as a super sale exclusive to Prime members. Last year's installment increased global sales more than 60% compared with the first year. Unlike past iterations, which ran 24 hours, this year promises an extra six hours of savings, stretching from Monday night until the end of the day Tuesday.