Not only does it have a browser extension - making it much easier to start tracking an item - but that extension also shows a graphical price history across three separate categories: sold by Amazon, 3rd party new, and used items.
Sure, it has its warts, with many to most owing to how Amazon has structured its data. For example, it can really only track price before shipping, so 3rd party new and used items can look like a bait-and-switch if the seller is using nosebleed-high shipping to paper over a price discount. Still, that does help a buyer to manually reject such “offers”, with the unfortunate side effect being alerts that they have to ignore.