Nor should it be. The standard for copyright violation is pretty high, things don’t have to just look similar, they need to actually match, so there’s no copyright over the idea of cute, Japanese-themed monsters, especially with other Japanese-themed monster games/shows like Digimon. Even if they matched the art style, you can’t copyright art style, you can only copyright the art itself.
He has cheaper ones too, so check around the shop and find one that fits your requirements.