Amazon Price Watch

If you're a smart fish, and refuse to pay more than what you consider a reasonable price, check out the Amazon PriceWatch tool, an IE or Firefox plug-in that monitors a particular item, and alerts you when the price for that item falls below the threshold amount you set. Some retailers offer postsale price protection guarantees if a product's price drops within a fixed number of days after you purchase it; Price Protectr will alert you if the price of an item you recently bought at any of up to 150 online retailers drops below what you paid for it.