You might not be aware that you can use Instacart to place a Costco order and have it delivered without a membership.
There are some items at Costco that are solely available to members, but using the Instacart app gives you access to a much wider range of goods.
How to shop at Costco with Instacart
Visit Instacart.com using your browser or the Instacart app.
Register a new account or sign in to one you already have.
Enter Instacart and find the Costco Storefront.
Fill your shopping cart with everything you want to buy.
Choose a delivery time and finish the checkout.