Buy one, get one free. In case customers decided to return one of the items, we wanted to make sure customers get some money in return. So we divided the discount evenly between the two items–thus 50% off both items, which is equal to 100% off a single item. Got it? If you don’t, then we have a problem.
So I’m ringing up a customer, and telling her how the discount works, so she knows she won’t return an item for 100%-off, getting $0.00 back. She looks at me, calmly stating, “Yes, I understand.” So I divide several pairs of items, 50/50, 50/50.
When I hand her the receipt, she looks at it, standing there for a moment. Then she looks at me, pushing it at me, “What is this? What did you do? I thought one item was free?”
“I explained it, and you said you understood. I guess you didn’t.”
Customer types: Liar, Deaf
P.S.
If you need a detailed explanation: you buy two items $40 and $40. I give you $40-off, splitting it $20 for one item and $20 for the other. Thus you pay $20 and $20 or $40 total. If you need to return one of these items, you still get $20 back. Buy one, get one free in value.
Memoirs of a Retail Salesperson 