Kirkland is giving away free samples of their premium diapers. These are great diapers that you can buy in bulk without the premium price. Diapers can be expensive so free diapers can always come in handy. If they work as well as what you currently use then you may also think about switching. This free sample does ask if you're a Costco Member, but doesn't require a membership number.
A random 12-digit number will work as a Costco id.
Be sure you also get the face cream samples.