It made me think they were either bad at math or exaggerating.
If it's used in the context you're suggesting then it's a meaningless snippet of information as it doesn't reveal anything about the typical user experience.
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.
