U.S. military operations against ISIS in Iraq have cost an average of $7.5 million per day since they began in mid-June, the Pentagon said on Friday, a figure that means the department may have spent about $500 million since it became involved."(The cost) has varied since the beginning in mid-June but on average it's costing about $7.5 million per day," said Rear Admiral John Kirby, the Pentagon press secretary. "That's based on a snapshot of the operations that have occurred as of the 26th of this month."