I use z sharetank, it’s normally a lot cheaper doing it that way as it’s seems to be cheaper than the local stations. An example currently to buy 91 on sharetank it’s 2.319 on Gaspy at the nearest z station it’s 2.409 after discounts. The cheapest around where I am is 2.387. So I just open the app, buy the gas before going to full up. If you’re really smart then you also change your flybuys to petrol discounts as well. Then once every couple of months you get an extra discount.