What about the following?

I buy $4000 worth of Costco Cash Cards with mm CIBC Master Card on line. And then use these
1. to shop at the store, gas etc.,
2. get cash as a return item,
3. get some cash as I am shopping and paying for goods at the checkout counter.

Or the Cash Cards are not "cashable" at all at the store. Has anyone any experience in cashing Cash Cards and if so any limit on this?

Any other stores that sell Gift Cards with no 'handling fees"?