What’s more important for the bottom line, though, is that Starbucks has proven to be highly innovative in the way it sells its main course: coffee. In 800 locations it has installed automatic espresso machines to speed up service. And several years ago, it began offering prepaid Starbucks cards, priced from $5 to $500, which clerks swipe through a reader to deduct a sale. That, says the company, cuts transaction times in half. Starbucks has sold $70 million of the cards.