Subscribe and save isn't too bad, but I agree, costco is definitely cheaper. Unfortunately in the metropolitan area without a car it's extremely difficult to get there. Have you guys checked out Boxed Wholesale? The prices are pretty comparable.
I did a comparison to Walmart a while back and Amazon was definitely pricier for bulk goods/detergent/etc. And I have one close by that I can easily drive to. If I lived in a city without a car, the savings in hassle might be worth it but otherwise doing a few runs to a local big box store each year is pretty low on my list of tasks to eliminate.
At least in San Francisco, Costco offers Google delivery for a subscription fee. I don't remember what it cost, but it didn't seem absurdly out of line.
I don't use that because I live three blocks from Costco and can just drop in for a couple of things, so I do usually just walk instead. Once every few months I rent a Zipcar to get huge bags of whatever home.
Legitimate question - do they pay their employees a living wage? What is the executive:average employee wage? Even if Costco were more expensive, I like to believe I'm helping our country out just by supporting a company that doesn't pay such a shit wage everyone collects welfare just to get by.