We go to Costco because of the 80/20 rule. You get 80% of the benefit for the first 20% of your effort.
Sure, we could beat the prices by a bit on several items, but not by a whole bunch and at the annoyance of going to other stores.
We find the gigantic Costco sizes to be an advantage, we don't need to shop as often.
There's bunch of stuff we buy at Costco every three weeks or so, then buy fresh veggies and specialty items at good local stores or farmers markets.
Sure, we could beat the prices by a bit on several items, but not by a whole bunch and at the annoyance of going to other stores.
We find the gigantic Costco sizes to be an advantage, we don't need to shop as often.
There's bunch of stuff we buy at Costco every three weeks or so, then buy fresh veggies and specialty items at good local stores or farmers markets.