You can shop at Costco without a membership card if you know of someone who is a member.
1. Tell your friend to purchase multiple cash cards for you and load each of them with $10 (which is the minimum for those cards)
2. Each time you shop at Costco, you enter the store with your cash card. After you shop, no matter how much your purchases cost, you use your cash card to pay the first $10 and pay the rest in cash. For example, if your purchase amount is $80, you use up one of your cash cards and pay the remaining $70 in cash.
3. At each visit, you use up one cash card.
I do not shop at Costco too often and I ordered (through my friend) 10 cash cards with $10 on each of them. 10 cards lasts me almost a year. And before you run out, you just order more.
Or, you can also use your friends membership card, but this is against the terms of the membership agreement.