Worked for a Midwest coffee chain (way longer than I should have). At one point the company brought in a new POS system that was truly a POS (pun totally intended, the company that sold it to us went bankrupt and also sold the software to said coffee chain).
One of my fellow employee found out that instead of ordering a usual food item and get the 30% employee discount, you could order toast and add any item as a topping for no additional charge, while still getting the 30% discount. Came out to $0.85. Named it the "toast hack"
You could have any sandwich you wanted, completely customisable. Smoked salmon, avocado sandwiches on multigain bread? 85 cents. Blts with extra extra bacon? 85 cents.
Lasted almost a year before corporate caught on.