Link is provided for reference only, the warehouse have lower price than Costco website. See picture for details, deal exp: 7/22/2018. The warehouse I went to is:
Costco Business Center
900 Dubuque Ave, South San Francisco, CA 94080
But the price should be the same throughout Costco Business Center. This product is probably not available in regular Costco warehouse, at least I haven't seen it there.
In terms of taste, my favorite used to be Twix before this came along, now this is my favorite. Keep in mind that this is not very healthy, so you should also buy a treadmill from Costco and put it in your living room, so you can stay in shape while you binge on this addictive Oreo Chocolate Candy Bar. I already ate 3 of them while posting this deal on SD, it melts in your mouth, very smooth. This same item is selling on amazon for $24, that's why I mainly use Amazon Prime for their streaming videos, I rarely shop their unless they have a good sale.