Son, that was rude, presumptive and wrong. Our Costco always has Choice
and Prime beef. I just got a Prime whole ribeye. Their price for the whole primal is about the same per pound as a grocery store for sliced Choice. They won't slice it for you, but I'd rather slice and trim it myself. Their price for sliced Prime is about double their price for sliced Choice.
In addition to regular availability of Prime, they occasionally have Wagyu. You can almost always order it at Costco online.
http://www.costco.com/CatalogSearch?keyword=wagyu&pageSize=96
So just because you've never seen it, doesn't mean Natrix "has no clue". In fact, I would argue the reverse.