If you are in need of some organization of your online shopping, you should definitely check out ShopSanity.
You can track all of your purchases, but the best part is this: "Get alerts when something you bought goes on sale so you can get a price adjustment!"
That's fantastic! Now you don't even have to look for yourself. You will not only be notified if an item you bought goes on sale, but you will be credited!
This is a free site and is certainly worth checking out!
Go here to sign up or to get more details.