But those laws don't seem to imply that the seller can't give 5 grilled cheeses when accepting a $5 bill. There is a possibility of buying just one grilled cheese, you give them $1. If the client chooses to produce a 5, after reading the rules, then whether they plan on eating more than one or not, it doesn't matter.
In this situation nobody is refusing to accept legal tender nor are they attempting to make "married sells" with items that can't be bought individually.
But those laws don't seem to imply that the seller can't give 5 grilled cheeses when accepting a $5 bill. There is a possibility of buying just one grilled cheese, you give them $1. If the client chooses to produce a 5, after reading the rules, then whether they plan on eating more than one or not, it doesn't matter.
In this situation nobody is refusing to accept legal tender nor are they attempting to make "married sells" with items that can't be bought individually.
If I give you a 5 and want only 1 sandwich, you can't reject my money, neither force me to buy 5 sandwiches.
If you give me a 5 you are purchasing 5 sandwiches.
Edit: nobody is forcing you to hand me a 5