Yeah, 2nd the comment on being careful about used tires and chasing the lowest price. Although legally you shouldn't, you can end up with stuff that doesn't meet the minimum NZ standard.
My little brother used the work in a tire shop. They replaced a lot of snow tires for a car import compliance company and those snow tires got sent to south Auckland to be sold to poor people who couldn't/didn't want to pay for new tires. Apparently they handle like rubbish, and aren't the safest tires to have your family rolling around on, which is why the compliance place had to change them out in the first place.
When I was young and broke I got bitten buying 2nd hand: after 1,000km the tire warped (had a big S bend in it) and the steel wires came out the side wall. Tire shop said it had been in an accident which busted the belts and it took time and distance for the defect to become apparent.

