Costco Cash Cards can only be bought by members, but they can be used by anyone at any Costco store in the US. The cards go from $10 to $100, with a $25 minimum if you buy online.
You could also ask a member to buy you a $10 Cash Card in person and then complete the purchase with a debit card.
If you're buying something with your Cash Card online, you'll have to pay a 5% surcharge over the posted price.