Log In I came across this site a while ago, and I use it every time I shop Amazon. I'm usually looking at electronics and other gadgets on Amazon, but it will work on any product on the site. Basically, it is a price tacker and it shows you the history of all the price fluctuations. Using this you'll know when to get the best deal. You can also sign up for alerts so you don't miss a good sale. Just thought I'd pass the word along. I'm not affiliated with the site...just a really big fan of it.
I found a site calledLog In. This site has price tracking for amazon, best buy, Microsoft, and many others. It alerts you via text and email when an object you want drops below a certain price. Check it out!
For Amazon, I simply add the things I want to my cart and watch the price changes over the course of a few days. I'll know what the lowest Amazon price is and know when to avoid overpaying for a given item. You don't need outside sites to do the grunt work, though I guess it's nice nonetheless.