Certain stores and credit cards offer price protection -- should the price on the item you purchased drop, they can refund the price difference. Making use of the price protection can be difficult. There are different timeframes depending on what you bought, where, and how, and you'd need to keep up with the prices of each item to know if it's dropped enough to make it worthwhile applying for the price protection.
PriceZombie's price protection tracker makes it easy. You tell us what you bought and when, and we notify you if the price drops.
To get started, view a product on the PriceZombie website, and click on the "Price Protection" link to register your purchase. You can also mark an item purchased directly from your Watchlist.