I've heard tag sale used a few times but always thought it was some sort of "puffery," an obvious exageration or fancy language meant to entice but isn't strictly factual. Like "Best burgers in the world" or "A slice of Heaven" or "Hurry! Hurry! Hurry!" Tage sale may have once usually meant a specific kind of sale and now is usually puffery. I've heard it so rarely I wouldn't be able to tell, though.