Bait advertising is so called because it offers a "bait" to draw customers to the store or business and they can get "caught" as a result.
Enticing prospective customers into stores when there are reasonable grounds for believing that the goods will not be in the store or are unlikely to be available for a reasonable time at the advertised price, is unlawful.
You must therefore be sure that reasonable stocks are available to satisfy the expected demand generated by any advertisement.
The definition of what is a "reasonable period" or "reasonable quantities" will vary from one situation to another, depending on the nature of the goods or services.
When offering goods for sale, you are expected to provide sufficient quantities of goods to meet anticipated demands, unless you clearly state otherwise.
You can specify exactly how many items are available for sale at the special price, providing you make it clear in the advertisement.
If you are unable to supply goods at the advertised price, you may offer a "rain-check" or equivalent goods at the advertised price to maintain goodwill.
You have the option of nominating the period of time for which such an offer is available. However, any restrictions must be stated clearly. For example, statements such as "Today only" or "Weekend Special" or "Only until Saturday" are acceptable, but must be clear to the reader.
The term "special price" means the price is a reduced or bargain price by comparison with on "ordinary" price. Once again, you must be able to substantiate that the goods were available at the "ordinary price" for a "reasonable" period.