Tires can be the value of the membership. Oil with a Costco coupon, potting soil in Spring, detergent and dish washing liquid are usually good deals. Pork chops and loin in addition to fish and the rotisserie chicken are usually great buys. We also buy the things we use all the time, Kirkland paper towels, toilet paper, olive oil, block cheese. Watch the fresh vegetables, often they are higher priced and well past prime to the point of rotten.
It takes time to learn what to buy and you have to comparison shop. The maga box of cereal may be a higher price than WalMart but the 10 pounds of King Arthur bread flour is a steal.
Going into that store was like us beaming in from Mars, since we have not been buyers club members before, after I read the research that says members tend to spend more annually than those who are not. What we're doing now is trying to figure out whether a membership in years where we don't buy expensive appliances is worth it price-wise. And also how much of our shopping list can be bought at Costco, since it is 20 miles farther from us that other alternatives. It won't be decided in one stop.
As far as tires, it'd be great to get a price on a set without having to enter my car license number. I know the size, and why I need to give them more information about me online, I dunno. Someday, I will ask at the store.
You mentioned olive oil. We did not see a recognizable brand of olive oil there. We buy high quality olive oil, of course as cheaply as we can get it, and brand can make a big difference. I did like the selection of frozen fish there but have not looked at pricing much on that though. We went into the cooler where the veggies are, Ms. Jswordy was leading, and she swept in there and back out pretty darned quickly, lol. The in-store auto oil selection was Kirkland or Mobil 1. 12 quarts of Kirkland full synthetic is $49.99. Six quarts of Havoline full synthetic at WM is 28.27 ... like $3 more for a name brand.
We did find a brand of blueberry jam that we had bought while in Maine. The jar was twice the size and cost a buck more than we found it at LL Bean Outlet. So a couple of those went in the cart.
Anyway, that's the kind of stuff we're checking out. At parties, I have eaten and loved their ultra-processed snack foods. They do have a bunch of stuff. They have Pellegrino in glass bottles, rare to not be in plastic here. Just looking over pricing and what works for us, is all. We're not done trying.
Gratuitous pic of the kitchen as Ms. Jswordy made the first meal in the new range ... because this is a photo topic! Kitchen is not done yet but very close. I will post a set when it is all completely done.