I got it once to buy a white goods item that Costco had which was a couple hundred dollars cheaper than anywhere else. Membership was worth it just for that one purchase. I used it one other time for groceries that year, but I don’t have a large family so bulk goods are not that useful. My normal shopping method is to keep an eye out for colesworth specials and buy extras of the things I regularly use. So Costco wasn’t useful for me for regular grocery shops, but if I had a big purchase to make I would check Costco prices against JB/good guys etc. If I lived quite close to one I might consider it for the discounted petrol though.