Wikipedia
Kumamon is a mascot created by the government of Kumamoto Prefecture, Japan. It was created in 2010 for a campaign called to draw tourists to the region after the Kyushu Shinkansen line opened. Kumamon subsequently became nationally popular, and in late 2011, was voted top in a nationwide survey of mascots, collectively known as yuru-chara, garnering over 280,000 votes. Following his success in the contest, Kumamoto earned in merchandising revenue for the first half of 2012, after having only earned throughout all of 2011.
The Bank of Japan estimates that in the two years prior to 2014, Kumamon generated in revenue.
The success of Kumamon can also be explained by the fact that Kumamoto Prefecture is selecting the products using Kumamon but is not charging any copyrights for the use of the character.