The chart below is for a pressure cooker that I was looking at a while ago:
As you can see, July 9th would have been a very bad day to purchase this product...costing $18.98 more than the day before or after. Incidentally, the price was a whopping $119.99 when I created the watch, but I could see from the chart that was the highest price ever. Without a tool like camelcamelcamel, you would probably never know.
To help make using camelcamelcamel easier, Josh Lewis posted a bookmarklet on his blog. This bookmarklet allows you to click the bookmark from any product page, and you will be immediately taken to the corresponding price chart at camelcamelcamel.
Unfortunately, the bookmarklet did not work on my iPhone...
It turns out that Amazon formats their page differently for use on the iPhone--and probably other smart phones as well. The bookmarklet was looking for information that just isn't there on the web pages sent to phones.
So...I modified it to work with either version of the Amazon webpage. If you want to try this, just bookmark the link below. Don't just click the link, because it won't work. On most browsers the easiest way to add it is to just drag the link to your bookmark list. The easiest way to add it on an iPhone is to add it from your computer in whichever browser you use to sync bookmarks to your iPhone, then perform a sync. Now, visit an Amazon product page, choose that bookmark, and you should see the price history graph appear.
As a note, camelcamelcamel is supported by affiliate revenue they receive when you click through their site to get to Amazon. So, if you like their service, use their links to get to Amazon, and you will help them stay around.