Get yourself a good grocery app. We add stuff as we are close to running out. We only buy what we need. We also have lists of where to buy everything we buy cheaply. So shopping is all about replacing the standard food items. The same things are bought each fortnight. I find I save more money by buying standard items than if I meal plan. Or if I do meal plan it's with ingredients I already have or know I'll have not with recipes I want to try or make that require ingredients I don't have.

I have done $120 a fortnight before. Crazy but true. I even did it once with 4 adults and 2 kids. I see most things that aren't ingredients as luxuries though. And generally steer clear. And I shop around between the woolies, costco, Aldi, our budget butcher and budget fruit and veg. These days probably about $150/week.