We've been members for years. When we lived in Japan, once we'd bought meat at Costco, we didnt dare buy meat at the local store. We typically went only once a month because it was an hour drive, plus $22 worth of road tolls. But we saved enough on a week's worth of meat to cover the tolls. Once we'd covered that, everything else was a no-brainer. And Costco was the only place to get a lot of American or American sized foods.
Back in the states, we consume steaks only about once per month, but Costco is the only place I know that you can get prime rib-eye "cap" steaks. This side of Kobe beef, that is IMHO the best you can buy. Pricey at $20 a pound, but since we eat only $25 of it a month, we'd prefer the good stuff. We live in "cherry country". Lots of them grown around here...but the absolute best cherries aren't at the fruit stands...they're at Costco, at about the same price or maybe just a tad more than the fruit stands. DW loves cherries, so from May thru July, we hit costco once a week for cherries and produce.
Finally, when we moved back to the States, we upgraded to executive membership which does cost more but comes with a rebate that way more than covers, for us, the membership fee.