I have heard that if I buy something in a store, and that price is reduced within a week or so, I am entitled to get the difference. Is that true?
Edit: Here is an example from Apple:
Should Apple reduce its price on any Apple-branded product within 14 calendar days from the date you receive your product, feel free to visit an Apple Retail Store or contact the Apple Contact Center at 1-800-676-2775 to request a refund or credit of the difference between the price you were charged and the current selling price. To receive the refund or credit you must contact Apple within 14 calendar days of the price change. Please note that this excludes limited-time price reductions, such as those that occur during special sales events, such as Black Friday or Cyber Monday.
From: http://www.apple.com/legal/sales-support/sales-policies/retail_us.html