大多数欧美市场的商品价格都以99分作为商品价格的结尾，这种做法开始于十九世纪末期。主要原因如下：

Goods are priced this way for a number of reasons, the predominant one of which is that people instinctively round the price down to the leading digit, so a price of $10.99 will be viewed as $10, which might persuade people to purchase as they subconsciously think they’re getting a bargain. It also gives the impression that the retailer has discounted the price from the next rounded number. Psychologists claim that another reason for people to be seduced by this kind of marketing is that they view the shopping experience more favorably if they receive change. By ending a price with ninety- nine cents, the retailer therefore gives the person the smallest amount of change possible, again maximizing profits.

Another possible reason for this kind of marketing is that people find the look of a combination of nines appealing The aesthetic value of something priced at $99.99, for example, might therefore make a person more inclined to purchase it.

It is also thought that the practice of such pricing actually started as a means of ensuring that cashiers had to open the cash register to give change, which made it more difficult for them simply to steal the money that had been given to them. Another, more compelling explanation is that it allows the use of gimmicks such as advertising goods as being “under $100”. By making the item $99.99, the retailer is true to his word and might succeed in luring the customer into the store where other items might then be purchased.

Some claim, however, that this method does not work because nine is a larger number than one and $99.99 has more digits than $100, and so seems more expensive. It can also prove counterproductive by causing confusion and annoyance among consumers, who might feel that they are being duped.