It’s a website that lets you sort amazon by price per ounce/pound/count
Some examples are:
Cheapest rice per pound https://bangyourbuck.com/search/rice/Lb/US/grid
Cheapest batteries by count: https://bangyourbuck.com/search/aa batteries/Count/US/grid
Hard drives by terabyte: https://bangyourbuck.com/search/hard drive/Terabyte/US/grid
Been using it for months, and I can’t stand using Amazon without it now.
I once went on a deep dive trying to figure out whether napkins or paper towels were cheaper I probably still have the spreadsheets.
I did the same thing with Kleenex vs toilet paper. TP won.