My prime membership purchase was a renewal, bought in May, I've been a member since June 2017. The price I was charged is not the 40% non-prime members reduction even, it's a 30% reduction. Something strange happened and this items sale was reduced to 30% off for everyone for a few hours, this was the price displayed when I checked this morning, but now it's gone back to the "correct" reduction. However as I said it's not important, I'll be more careful in future.