I bought a Costco membership two years ago. Did not see any benefit from them, and their prices for just about everything is higher than what I can get from Wal-mart or Target and other local retailers. The only benefit I got from Costco was the lower-priced gas, but then, it amounted to just a few dollars savings for a year. Last month,I dropped my membership. Costco did offer higher pay than Wal-mart of Target, but that advantage has disappeared in the last few years with the higher-wage demands of recent years. But, the higher wages also meant higher prices for their goods, therefore, it was not for me.
Not everything at Costco is cheaper than Wal-Mart, but most items are. Costco has much better quality in almost all product categories.
AS an example, if a person needs Claratin for allergies, the price for the Kirkland brand is $4.49 for the D-24. Everywhere else is 3-5 times higher.
Meat prices are also very reasonable, and the quality is Choice or Prime grade.
Bread prices are much lower at Costco, as are most frozen foods and dairy products. Milk is a possible exception since Kroger has milk on sale most of the time.
I gave up on Costco when they went from tradesmen only: farmers, loggers, commercial fishermen, mechanics to allowing nurses - after that I only went there for specific items, and only if the round trip gas bill was not a factor.
Last trip - over 10 years ago, as the nearest stores are 30 miles away.