I find that there is lots of waste in my buying habits for a couple reasons; I typically only need half or so of the buy able serving size of many things, but would prefer the prices of bulk items.
An interesting model would be to allow several people, ideally geographically close to one another, but not necessarily friends with eachother, to build a communal list of standard/often purchased items.
When some threshold is met, the items are purchased and divided among the buyers.
The items would need to be divisible easily by the number of buyers...
A service like this should also focus on minimalist packaging.
Set the fee at stepped level, $25 $50 $75 $100 -- and I just have a running list of items I use regularly. When enough people need the same things and my buy threshold is met, the box ships, I am billed and the counter restarts until the next month/interval.
There should be a simple way to report how quickly you consume an item and the system would determine the larger average consumption rates over time and make suggestions on how often items should be added.