Actually, exactly this (from apple dev)
Quote: "Display prices clearly, using the locale and currency returned by the App Store. Ensure that the price of a product is easy to find and easy to read. Don’t try to convert the price to a different currency in your UI, even if the user’s locale and the price’s locale differ. Consider, for example, a user in the United States who prefers the United Kingdom locale for its units and date formatting. Your app displays its UI according to the United Kingdom locale, but it still needs to display product information in the locale specified by the App Store. Converting prices to British pounds sterling, in an attempt to match the United Kingdom locale of the rest of the interface, would be incorrect. The user has an App Store account in the United States and pays in U.S. dollars, so prices would be provided to your app in U.S. dollars. Likewise, your app would display its prices in U.S. dollars. Listing 2-3 shows how to correctly format a price by using the product’s locale information."
