It all depends on how close it is, what you usually buy from elsewhere and whether you feel it is worth it. We have been Costco members for over 15 years and it was on Dh's way home from work so easy to call into. However we are executive members so get in an hour before individual card holders and get 2% cashback on all purchases which pays for the card and an additional card holder with the amount we spend in there.
Every couple of years I do a price comparison between Costco and Asda/Aldi as those are our 2 main shops. Back in the day when a 4 pint of milk was 99p in the supermarket, Costco had a 2 pack for £1.69 so that in itself was a massive saving for us when the children were little and again as teens. We have a set list of things we buy because we feel the quality is better in that I include bin liners (but it will be a pack of 90) black bin bags, tin foil, cling film and parchment paper. Stuff we buy on offer Finish dishwasher tablets that we buy a year a time.
Regular items we buy and remember this will be in bulk so toilet roll (40 rolls in a pack) tinned tomatoes (12) tuna (12), sweetcorn, frozen salmon which are massive fillets compared to supermarket ones, huge block of cheddar, babybel cheese, applewood smoked, all 3 cheeses are considerably cheaper. Minced steak, pork shoulder (3.2kg ish compared to the supermarket's 2,6kg from Asda, I like left over pulled pork for nachos) and chicken breast. And tortilla chips and pistachios.
We also buy petrol from there too. It works for us. some items we save on like toothpaste some items we don't but it sort of evens out. And you cannot beat their hot chicken for taste, or the price of a massive cooked pizza at their cafe. We have also bought footwear, socks, branded items cheaper, books etc.
We have a larder freezer, a vacuum food saver things for dividing and freezing portions and a massive pantry to store all the dry goods. Not everyone does. This is a bit like asking if you like Asda and there will be people saying yes, those saying no and those saying this is better or that is better etc. The best way is to try to go with someone who has a card and then do a price check against what you usually buy.
We bought a TV from them years ago, about 4 years in the on/off button broke but Costco has a 5 year guarantee so they arranged for someone to come out and fix it. Then rang us up to check the company and person were polite, did the job and were we happy with the outcome.