Percentage discounting campaigns
Advertising campaigns that state "Up to 50% off" are likely to cause consumers to believe a number of items are discounted by 50 per cent and that all other items within the store will also be discounted to some degree.
You should not advertise this type of saving if only a few items are offered at 50 per cent off and the remaining items in the store are offered with little or no discount at all.
You must be able to show that the customer is really saving money.
If you wish to limit the stock included in this type of campaign, you could use terms like "Up to X% off all CDs" or "Up to X% off selected items".
The test is that it must be clear to the consumer that not all stock is discounted.