Bach and others' rhetoric implies that your Starbucks coffee is wildly over priced and you're better off without it. But an article at the Washington Post counters the first claim. Unpretentiously titled "Why a 12-ounce latte costs $3.25", the article outlines the major costs in producing the latte as follows:
Cost to consumer $3.25After expenses coffee shops are only left with a 9% margin on the latte. That's well within general retail norms. Even for Starbucks or other major chains (the numbers above reflect independent stores) the profit only rises to a 13% margin which is hardly exorbitant. As the article notes, the latte is an expensive drink for shops to make because of the milk and additional labor over regular coffee. The regular coffee would probably have a higher margin. Starbucks makes a killing on large sales volume. The only thing getting killed on your particular latte purchase is your wallet.
Cost to coffee shop $2.96
Profit to coffee shop $.29