Not sure if the proper term is coupon or voucher. I get the impressions there is a subtle difference, so forgive me if I am confusing the two.
I believe they exist, but not sure if they have a significant impact on grocery costs.
My wife has joined the cult of couponing in the US and has probably cut 1/3 off our grocery bills recently. She's gotten quite good at using store double coupons with specials and manufacturer coupons, and sees it as sport in addition to cost savings.
Is this common in NZ? Do stores double coupons? Are there websites to help track coupon specials among the various grocers?