When a company or organization offers a service for free, they are not making any money to pay their staff or to pay for the content they provide. For this reason, these apps and services use ads and partners. By having ad breaks and ads for users that are using the service for free, the service provider can make money to keep the service free, maintain the servers and provide the staff with payment for their work. If you are using a free TV service that is not using ads to make money, there is a rather big chance that the app or service uses illegal practices to get its content.