Unless you go for the really high-end stuff, it's a few cents a day to drink a couple of cups at home in the morning.

In a seller's market for labor, free coffee makes a useful pons asinorum for potential employers, whether or not you drink it at work. (I don't.) Even in overpriced packaging methods like K-cups, it's so inexpensive in bulk that a company that cheaps out there will cheap out on more important things too. Similarly, because caffeine is a performance-enhancing drug for cognitive workers, one may reasonably question the good sense of leadership which refuses to provide it free of charge.