What follows is a moderately paraphrased conversation I had yesterday with my wife, Meredith, who loves Starbucks as much as I do... and possibly more.
Meredith: "I have a Star Streak on my account right now... if I make five purchases, I'll get 150 bonus stars."
David: "That's one free coffee."
D: "So... you have to buy five coffees to get one at no charge. And your average coffee costs around $8... so you're spending $40 to get $8 for free."
M: "Well, when you put it that way, it doesn't sound like such a great deal. Maybe I should use my Stars to pay for my Oat Milk instead?"
For the uninitiated, Starbucks has recently begun offering Oat Milk, which Meredith absolutely loves in her lattes. Starbucks charges an extra $0.80 for everything that's not "regular" milk -- i.e. Almond Milk, Soy Milk, Lactose-Free Milk, and now, Oat Milk -- but you have the option of using 25 Stars to pay for any alternate milk selection instead.
Now, here's the interesting part.
"How much is a Star worth, anyway?"
That, my friends, is the magic of the Starbucks Rewards program: they don't use actual currency for their rewards, they use "Stars". And the value of a Star depends entirely on how you choose to use it... so nobody really knows what one Star is actually worth.