I've used this extension for years and it's saved me quite a bit of money. Unfortunately, I've had to uninstall it as it messes up the HTML code of several websites with sticky top menus.

Most of the time the results show the same one I've already picked out or something else entirely (ad?) although I only really look at it when I'm comparing it to what I'm actively purchasing or on pages that have nothing to do with a purchase. Otherwise, the main reason for three stars is everything I look up gets sent to Google search. I'll use this when this becomes more relevant and repaired.