Massive discounts and flamboyant promotions for consumers during China's annual Singles Day in November, known as 11.11, help to create the country's biggest shopping day of the year. But not everything is as inexpensive as consumers believe, and online shoppers have actually paid more for some products during the festival, according to a report by Bain & Company.

Although the higher average prices were mainly led by increases in imported products -- notably for toothbrushes and sanitary protection products -- Bruno Lannes, a partner with Bain, cited other factors. For categories such as toilet and facial tissue, which did not see an increase in import volume, the higher prices were "driven simply by the marketing of the leading brands actually using 11.11 to promote the premiumization of these categories," Lannes said.