Supercheap Auto - 20% off your next purchase!
Just walk into any store, purcahse an item and ask them about the promotion (signs and posters should be up). All you need to provide is your name and an email address which will sign you up for the "Ignition" sales catalogues/newsletters each month. A confirmation email will be sent to you, and you can print off your 20% off voucher!
Alternatively, each store should have little business cards with a promo-code printed on them. Just walk in and grab one and register on the deal link here.
Technically the cashier should ask you if you want to register. I walked in without buying anything and the cashier gave me the promo signup anyway.
Voucher expires one month after you confirm the registration. Only 1 voucher per registration.
Not sure when the promo ends.