This is apparently a subject of debate (see: http://skeptics.stackexchange.com/questions/2359/the-origin-of-99-cents http://skeptics.stackexchange.com/questions

This is apparently a subject of debate (see: http://skeptics.stackexchange.com/questions/2359/the-origin-of-99-cents http://skeptics.stackexchange.com/questions/2359/the-origin-...) Most sources agree that its origins are in psychology, though your theory may explain its widespread adoption by retailers: http://www.helium.com/items/705308-the-history-of-odd-retail-prices-eg-999 http://www.helium.com/items/705308-the-history-of-odd-retail... http://www.eurekalert.org/pub_releases/2011-09/ru-9pm090611.php http://www.eurekalert.org/pub_releases/2011-09/ru-9pm090611....