Wellness retreats in New Zealand are a real, established category—so your merch should feel like retreat gear, not throwaway freebies. The simplest high-impact option is a Welcome Kit: an insulated drink bottle, an A5 journal + quality pen, a sleep mask, and a cotton tote or zip pouch to hold it all. Brand it subtly (small placement, calm colours, optional embroidery) so it looks premium and actually gets used after guests go home. Match items to the schedule—hydration for movement sessions, journaling for workshops, and sleep support for wind-down—so everything feels intentional.