Utomik uses Coupon Codes to provide special offers, such as a longer free period. In contrary to other websites, Coupon Codes are entered when registering, not during checkout.
Some coupon codes are valid across the entire site, eg. no matter via which page you register the code is valid. Others require the code to be used on a specific promo url. The page will prompt you when you are trying to use a code on an invalid page and gives you to correct link.