I used to use the cotton bags – but they flop too much. Costco has returned the best reusable bags for sale… they’re blue nylon with red handles – they have a flat bottom when they’re open. They have slots for 4 wine bottles on the side. They are INCREDIBLY strong and can be packed full. Because of the flat bottom and the stiffness of the nylon – they can be put in the back of a car and not flop over, rolling all the contents around the back.
These are NOT to be confused with the awful green costco branded reusable bags… those are too big/unwieldy and have the same floppiness of the cotton bags.
These blue ones are inexpensive. I think it’s 5 bags for $6 or something. I bought 10 of them when they first had them 4 years ago… then they switched out to these oversized green ones that were useless… I recently purchased more blue ones when I saw they had them in stock again.
We use them for groceries, for hauling sporting gear, etc…