Amazon Price Watch 1.2.1
Amazon Price Watch is a great tool to save money on Amazon.com through refunds.
Because Amazon.com has Post-Order Price Guarantee Police:
"Amazon.com's prices for released items will change from time to time based on a variety of factors. If Amazon.com's price for an already-released item decreases within 30 days after we ship the item to you, we'll be glad to refund the difference in price if you contact us."