Allow us to breakdown why these tumblers, of all the Starbucks tumblers, seem to frenzy customers the most: First, each tumbler comes in one color but turns into another when exposed to cold liquids. Not only do you get a transformation, but you get two colors for the price of one. Second, these tumblers are sold in packs of five that retail for $18.95, so each cup (lid and straw included) comes in at just under $4.