If you read the article carefully, they actually did swing a specify tuition discount for their employees from ASU - before any federal aid is applied. What the school cleared up is that Starbucks didn't contribute any actual cash up front for the deal, but they did use corporate clout to guarantee low wage workers the initial discount.
"Instead, Arizona State will essentially charge workers less than the sticker price for online tuition. Much of the remainder would likely be covered by federal aid since most Starbucks workers don't earn a lot of money."
But that's only for the first two years.
"The program would work much the same way for the junior and senior years, except that Starbucks would reimburse workers for their out of pocket costs, once they completed 21 credits."
So, the school and federal grants are taking care of the first two years, and Starbucks is taking care of about $1000 out of pocket for the last two years (when prices do increase). An existing similar program being phased out in 2015 has already cost the company $6.5 million, and they have no guarantee that they will retain graduates as employees.