It does save money on occasion, but the constant pop-ups of useless info are really annoying - and there's no option to disable them without disabling the entire extension. Useless info being things like: 'you found the best deal!' or 'doesn't work for this page' or whatever. The ONLY time I want a pop-up is if there's opportunity for savings in excess of some threshold value of the item cost; say 5% or $5 - could be user variable in the settings! It'd also be great to be able to blacklist some vendors, like ebay. That said, I'm surprised there are so few users of this add-on. I wonder if there's a better one that I'm not aware of...