answer:Prime Pantry charges flat rate for shipping for each box. You can put one thing in the box, or you can fill the whole box. Same shipping rate. The shipping cost is the same as the upgrade to One Day shipping on any normal Prime order. They do often have deals that can get you free shipping, though – buy five of a certain selection of items, or whatever. I haven’t tried Pantry myself yet (building up my credits). I have Prime Now in my area, and that is super cool. You can get stuff within an hour if you really need it. Great for if you are in the middle of cooking for a dinner party and realise you’ve forgotten the chicken broth or whatever, and can’t leave the rising bread dough alone for that long. There’s a $25 minimum, but it’s easy to find $25 worth of stuff you need around the house anyway. Source: I work for Glamazon customer service right now. And they make me say that anything I write here is my own opinion and not a reflection of blahblahblahblah…