Online prices change often, and a listing's current price doesn't tell you whether it's actually a good deal. A price tracker extension charts a product's price history directly on the page, and can notify you when the price drops to a level you set, which helps you time a purchase instead of guessing.
How price history charts work
A price tracker extension records a product's price at intervals and plots it as a chart directly on the product page, often going back months or longer. This shows whether the current price is a genuine low, a temporary sale, or actually higher than the product has been recently, before you decide to buy.
Setting price drop alerts
Most price tracker extensions let you set a target price for a product and send a notification, usually by email or browser alert, when the price drops to or below it. This means you don't need to keep checking a listing manually while waiting for a sale on something you want.
Amazon price tracking vs other retailers
Extensions like Keepa specialize in Amazon price tracker extension features because Amazon's pricing changes frequently and its scale makes historical data valuable. Coverage for other retailers varies more by extension, so check a tool's supported sites before relying on it for non-Amazon purchases.