What is the ruling on purchasing an application in exchange for watching advertisements?

If the advertisements are permissible to view or mostly so, then there is no harm in making them a payment for downloading applications. However, if they are forbidden or mostly forbidden, then it is not permissible; because the Prophet, peace and blessings be be upon him, said: "Indeed, Allah Almighty, if He forbids the eating of something, He forbids its price." And forbidden benefits cannot be exchanged for compensation.