Free Starbucks Coffee? You decide!

So when I hear the words "Free Coffee" I'm pretty much automatically in. Starbucks is offering free coffee for the entire month of January if you buy their Refill Tumbler at their stores! The only catch? The tumbler is $40. 

Now hang on, hang on, before you write it off... let's check out the math. If you took advantage of the free coffee or tea every single day of the promotion, you're looking at $90 worth of Starbucks! Minus the price of the $40 cup, you're still gaining $50 worth of free coffee.  Not too shabby in my opinion!