I can't directly answer your question, but indirectly....... I shopped them long ago and their prices on batteries are cheaper than most other places. They offer two types of packaging (I don't know what it is currently, but....) . They'll have 3 or 4 sets of 4 in a package that are designed for resale and they'll have bulk packs with singles like 16 or 24 or whatever. Obviously the ones for resale are more expensive than the bulk.
Even though I found them to be cheaper, I found that if I bought cells when they were on sale, I could get them cheaper still. I stock up on them whenever they're on sale and I usually pay 20-25¢ for AAs & AAAs.
If you're not a shopper, then you'll still save a little comparing apples to apples at Costco. They have their own brand of AAs in a bulk pack that everyone seems to like and they are quite a bit less.
I couldn't do without my Costco membership. I trust their products and they have great customer service. They have the best electronics return policy anywhere (one year electronics and six months on computer stuff). I've been a member since the 80's.
The only problem is when I go in to pick up one item, it seems I can't get out of there for less than $50 - $100.