can I exchange iPhone 5 by iPhone 7, cause I heard rumors we can.

I heard rumors people exchanging iPhone 5 by iPhone 7 just by paying 50$ or some thing close to that, so I want to know...cause if it's possible I would like to change my iPhone 5s iOS version of 10.3.1 (14E304) into iPhone 7+ RED... even if it means I have to pay 200$, so help me out here people.