My girl was looking for a dress for Halloween. Yesterday she found one on Amazon for € 35 and put it in the cart, but did not buy it. Today she looked it up again and it was € 50 so she asked me to look it up with my phone with my Amazon account - it turned out to be € 23 for me, less than half of what it’s for her!
It’s often a checkbox in green near the checkout button if the item and can be the most absurd percentages that shift daily and are often better discounts than sale days.