If I'm not mistaken in CN Ronin Naruto was released at 2* - maybe that has something to do with the lower price in CN, we also have to keep in mind that CN is very different from western servers.

Right now, if Naruto ronin was made avaliable for 2.4k coupons it would cause chaos, especially in the newer servers.

Ronin Naruto is slowly starting to appear on more events, so I guess you can get him for cheaper than that in the future (?) if you can get him in multiple events at the same time.