Practical information : Treat yourself (& others) New Zealand
Timetable
The stores have fairly standard opening hours: from 9-10am to 5-6pm. Some are open 7 days a week, others close one day a week.
No big malls in New Zealand, the shopping culture is not very widespread. A few shopping centers here and there regrouping the biggest brands, but nothing crazy.
Budget & Tips
Gear up. If you're looking for inexpensive equipment for your vacation, the references here are The Wharehouse and Kmart, a Gifi-style store where you can find a little bit of everything for less. If you're looking for electronic equipment (adaptors, new cables, new headphones...), Noel Lemmings is the place to go, and for outdoor gear, you'll need to visit Mountain Wharehouse, Kathmandu or Macpac, or Ice Breaker if you want high-quality merino wool clothing, another local specialty!
Cheap tip: look for second-hand treasures. If you're a bargain-hunter, you're sure to find what you're looking for here! Second-hand shopping is widespread, and so-called "op shops" (opportunity shops) can be found all over the area. Salvation Army, Saint Vincent de Paul, City Mission, Mary Potter Hospice Shop, St John, SPCA Op Shop, Savemart, Red Cross Shop, to name but a few. There's even a website that lists them and allows you to search by city or brand! https://opshopdirectory.co.nz/
Sales
As in Europe, there are two sales periods during the year: at the end of winter and at the end of summer.
Many retailers also have sales on Black Friday but nothing like the craziness of the American continent.
What's very local
Local crafts. If you're looking for products/souvenirs that showcase local craftsmanship, the best thing to do is hunt out "pop-up stores", small temporary stores that showcase the work of local artists and merchants. You'll find all kinds of objects, jewelry and artworks printed on posters, cards, bags, mugs, cushions and other materials. Guaranteed to find something highly representative of the country!
Māori arts and crafts. When it comes to traditional Māori art and crafts, it can be hard to find good addresses. Souvenir stores often offer traditional necklaces and pendants made from pounamu (jade stone), but chances are they are manufactured products, or even that the raw materials used are not from Aotearoa. Overall, price is a good way of assessing authenticity. You should expect to pay at least $100-200 for a quality piece. Sometimes a little less for smaller models with a slightly more basic design.
Ngāi Tahu, the South Island's main iwi (tribe), has set up an authentication system for pounamu: a logo ensures that it is indeed a New Zealand stone, and a tracing number makes it possible to see exactly where it was extracted from and which artist made it. A product showing this logo is therefore guaranteed to be genuine, but not all genuine products carry the logo. See their website for more information: https://ngaitahupounamu.com/
Generally speaking, museum stores are good places to find authentic products.
Don't hesitate to visit your local tourist office for recommendations on where to go to find what you're looking for.