I think you're counting all sprint employees, even field workers and store employees, but the free snacks were only available in the corporate office. Also, I think you're assume 365 days/year, but the snacks were likely only available for ~ 253 workdays/year.

According to Wikipedia, the corporate office has around 7,000 full time employees (not including 4,000 contract workers), so the company could have saved as much as much as 35 cents per employee per day.