Or to their cell provider. My wife upgraded from an 8 to 12 mini for “free with qualifying trade-in.” They charge for the new one and give her a credit on the same bill. Keeps her as a customer and isn’t exactly like a subsidized device, but pretty close. Credit depends on condition of the device body and display. Her’s was perfect, aside from a non-functional home button, and they are giving her full credit.
As an aside, the 12 mini is more impressive than I would’ve thought. As a 12 Pro Max user I would be happy with the 12 mini too. The size is fantastic and the screen is larger than I thought it would be in a device that small. Battery life (no 5G service) is better than the 8 it replaced when it had a fresh battery. She loves it.