Flour

The browser add-on is called honey, and it seems to be available for other OS. Can Google it and see if they have anything that will work in your environment.

Using a browser addon that tracks price history, we found a bunch of “deals” on Amazon US that had raised the price 30 days ago and are now flagged “Lowest price in 30 days!”. The “deal” price was almost always the exact same price it was 31 days prior.