May get some hate for how cheap this is - but may come in useful if you’re really penny pinching.
When paying by card at self checkout at Countdown (and, I’m assuming any other self checkout), go “split payment”, round down to the nearest 5 cents - the transaction will go thorough as complete and not ask for the additional 5 cents.
When going to Countdown, park as close as you can to the exit and walk the rest of the way. Doing this a few times a week can save you at least $0.05 in fuel.