They're listed in the Krause coin catalogue as KM/C# 7 with a price ranging from $5 to $17, depending on condition.
Krause also notes that "varieties exist"; the zeno.ru pages go into more detail on this. There probably isn't too much demand for the varieties outside of Japan.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis