RefundPlease.com is a great tool for Amazon shoppers. By entering your purchase information (ISNB number or ASIN number, Price and Dateand email address after buying from Amazon, RefundPlease will watch your item for 30 days, then alert you if the price has dropped. Then you can follow instructions to get your refund of the price difference from Amazon.

Currently, only Amazon is supported, but RefundPlease says that other retailers will be added in "the days and weeks ahead." So far, the site claims to have saved consumers $121,704.29 in price drop refunds.