Costco almost isn't a fair way to compare prices because they have intentionally been losing margin and raising prices as slowly as possible to retain customers.
https://www.macrotrends.net/stocks/charts/COST/costco/profit...
Ok, then let's look at my local Safeway. Shit is OUTRAGEOUS. If you don't think groceries haven't gone up 30/40/50% then apparently you don't look at any prices while you shop.
Look here: https://www.rabato.com/us/shoprite/weekly-ad/LEipqw
And here: https://www.rabato.com/us/shoprite/weekly-ad/KZiQw3p
Things are not 50%. Some items, some brands, yes. But you can always cherry-pick anything, always.
Chicken is actually CHEAPER today. Crazy (but that was covid supply chain issues I guess, so now I'm cherry-picking)