excluding the kello kit tiara with the ears that it comes with, I don't think this is a costume. It's just a regular dress with lower quality.

Some Macy's store has a section with hello kitty themed clothes where I found the cutest hello kitty dress ever! After I found this dress I started to keep second thoughts on what I paid for this dress.

But you won't find a dress with a huge hello kitty head on the front like this one of course. I would say I found cute clothes, dresses and even tutu hello kitty skirts at Macy's. The quality also is good and it's something you can have your girl wearing on regular days, different from this costume that would be fine to use in a party only once.