Just how good of a deal is that Amazon price?
If you're going to... shop online at Amazon,
you might as well... make informed purchases based on historical prices!
How does it work?
Keepa is both a website and a desktop browser app. With the app installed, whenever you open an Amazon product page, a little widget displays product pricing for the past 3 months. You may adjust the time period. This allows you to see how much Amazon's current price is discounted, if at all. If it's too expensive, you can set a price tracker, which will notify you when the price drops below a threshold value that you set.
The app is great when you know what you want and just need to verify if it's a good price. Now, if you'd like to browse for great deals, visit the site instead. You can browse by categories such as Electronics or filter results by, say, Lightning Deals or fufilled by Amazon only. The results page will show you items sorted by greatest % off. It's a really great tool to help you shop for items when you have a budget in mind or need gift ideas.