The U.K. Advertising Standards Agency (ASA) has upheld a complaint claiming that a TV advertisement with a "prices may vary" disclaimer was misleading because the complainant was unable to purchase the product for the stated price. Created by Kentucky Fried Chicken (Great Britain) Ltd. (KFC), the commercial in question indicated that families could "save a fiver" by purchasing "the new KFC Family Burger Box," instead of buying the components a la carte. On-screen text apparently clarified, "Item[] shown £20.51 if bought individually. Prices may vary."

According to ASA, Kentucky Fried Chicken explained that the phrase "prices may vary" "referred to both the a la carte menu pricing of individual items, the price of the Family Burger Box and the exact saving made between those two prices." To convey this information, the company chose the text "prices may vary" rather than "price may vary" "to be clear that this referred to all the prices quoted in the ad." In addition, Kentucky Fried Chicken argued that even though it was "legally unable to fix pricing within all the franchisee stores, and could only recommend pricing," the adjusted menu prices in the stores selling the Family Burger Box for more than £14.99 still led to consumer savings of at least £5. Clearcast, which approves TV advertising in the United Kingdom, endorsed this reasoning, adding that the guidance on "price may vary" claims "has been in place for over six years, without complaint from viewers."

Although ASA acknowledged that most restaurants sold the Family Burger Box at the quoted price and that "the savings in all stores was over £5," the agency nevertheless found that "the ad did not explicitly state whether ‘prices may vary’ referred to the items totaling £20.51, the Family Burger Box price of £14.99, or both." As a result, ASA concluded that "it was not sufficiently clear that ‘prices may vary’ referred to all prices quoted in the ad," ruling that the commercial breached the rules for misleading advertising, substantiation and prices.