Chicken sandwich deal
When one enters into a purchase of an item or service at a significant discount. This is also commonly referred to as a 'deal' etc.
Tupes and I got a chicken sandwich deal on those new tires.
Deal Sandwich
The result of a negotiation where one party winds up with something of little or no value while the other gains everything they wanted.
"She may have gotten the car, the house, the kids, the holiday home and every penny I had, but at least I got this deal sandwich."