Tool lets you search for amazon items based on price per unit/pound!
BangYourBuck - flour by the Pound - US - Grid View
https://bangyourbuck.com/search/flour/Lb/US/grid
Get the most bang for your buck with this per-unit shopping engine!
If you can't find a good place to buy a specific ingredient for cheap near you, you can see if it's cheaper on amazon based on price per pound. Really nice if you can't find something local.
It's not perfect if the lister messed up the info, but it's a great place to start.