Kylie posted this video on her Keek: http://www.keek.com/KylieJenner#kNGvaab
She has two of the same rings, see them here. They were $15 each, but are currently out of stock! ShopJeen also has it in silver, but it’s out of stock, too!!
It is very unique, and I didn’t see many similar rings online.. but I did find this ($62), which is close! ShopJeen is good about restocking items, so email them or check back, and you might get lucky!