My iMac runs High Sierra, and I use Safari. Both are fully updated.
This week, I am presented with recurring popups advertising Amazon Prime Day. I have cleared Safari's caches and cookies for all sites Amazon and Prime. "Block popups" is checked in Safari > Preferences > Privacy > Manage Website Data. Safari also runs the Safari extension Wipr, which is likewise up to date. Quits-and-restarts, both of the OS and Safari, are unavailing.
While the popups are easily dismissed, they're annoying. Other than these, I don't see popups or ads.
Have any of you ideas how I might successfully block them, or find their source?