Dresses like girls from SNSD wear?

Well, I doubt there are any places where you can get them here except maybe try Forever 21. It was founded by a Korean couple in the 1980's so the style has some Asian roots, I'd expect. Also try YesStyle if you have small boutiques of them near you. If not, you can check out their site. Shipping in the U.S. is only 9.99.