13 points
*
Here’s bread from Walmart for about $0.06 per slice.
Here’s cheese for $0.10 per slice
https://www.walmart.com/ip/Great-Value-Sweet-Cream-Salted-Butter-16-oz/132893363?athbdg=L1200
And butter for about $0.25 per ounce (you might use .5 oz per sandwich.) EDIT: checked my butter in my fridge, you’re probably using 1/4 of an ounce per sandwich if that.
And none of these are in bulk, you can probably cut the cost in half or less buying even more generic products in bulk.