20/20: Too Good to be True?

20/20 investigates popular products and services that seem too good to be true. Reports on a treatment called Lipodissolve, paying full price versus negotiating for discounts at stores, so-called luxury low-cost vacation packages, and foot pads that supposedly help detoxify your body while you sleep. Then, a preview of National Geographic's special, "The Human Footprint," hosted by Elizabeth Vargas.