Agreed. It's bad math. Even if they gave away something every now and then, it definitely does not explain 100% off. They would have to give away everything and

Agreed. It's bad math. Even if they gave away something every now and then, it definitely does not explain 100% off. They would have to give away everything and make money some other way (say shipping) - which could be plausible, but I don't see it explained here.