Common Amazon deception. Mark up a product's base cost artificially, then take a "percentage off" to bring it back down to near the base price it always is. Maybe slightly more expensive or cheaper, but usually just a smidge away from the normal cost. It's for the illusion of "being on sale."
Use an Amazon price tracker site (like camel camel camel for example) so that you can always call out Amazon and make sure that you're getting their actual lowest prices when you have to buy from them.
A handful of years back, JC Penney made a huge deal about stopping this practice in their stores, where everything is on “sale” all the time. Sales plummeted even though the actual product prices stayed the same. They immediately reversed course.
Penneys also stopped accepting coupons and it turned out that most of the older ladies who made up the lion’s share of the clientele loved coupons (who would have thought?). They also hired a retail exec from Apple (Ron Johnson) and he embarked on disasterous changes to stores and other things that regular customers hated. This is a great article that is titled “The J.C. penney Disaster Timeline” from 2012: https://www.businessinsider.com/the-jcpenney-disaster-timeline-how-ex-apple-guru-ron-johnson-is-destroying-the-company-2012-6
Furniture stores are infamous for that. They make a big deal of closing down for a day and marking every item in the store with a big discount, but what they don't tell you is they jack the price way up first before applying the discount.