A method for guaranteeing a consumer a best price on an item purchased from a vendor in a first transaction at a first price, the method including recording the first price and information identifying the consumer, monitoring the sales price of the item for a predetermined time period after the first transaction, noting any price lower than the first price for the item during the predetermined time period, calculating a money-value difference between the first price and said any price lower than the first price, and refunding to the consumer an amount equal to the money-value difference.