There's Amazon Pantry, which has you adding items to a box, which is only sent when full. Thus the mark-up remains quite low.

I looked into it a while back. The conclusion I reached was that it might be worth it if driving to the grocery store/Walmart, shopping, and bringing your supplies home was a hassle for some reason. But Walmart tended to be cheaper than even Prime Pantry and you have to be somewhat selective in shopping in Amazon. (You'll find some items are randomly pricing.)

In my case, there's a Walmart I can drive to in about 5 minutes so stocking up on paper towels and dishwashing detergent every few months (and/or when I'm at the grocery store anyway) is pretty easy.