Onyx Hospitality Group New Promo Code!! Enjoy 2,015 THB Spa or Food and Beverage Credit. Get 2,015 Baht for Spa or Food and Beverage Credit per room per stay when you book our Best Available Rate for a minimum of 4 nights. Use Promo Code: THB2015. Subject to availability, standard booking and cancellation policies apply. Promo Code cannot be combined with packages.