Look at the Vizio Smartcast. This option is at least free. But it... well it doesn't have the best ratings to be honest. But it might work for what you're trying to do. https/www.vizio.com/smartcast-how-to-cast
Also look at the Google Chromecast stick. It's not free, but it's less than an Apple TV. It won't let you mirror the phone to the tv but it should let you stream files local on your phone to the TV. This is a quick article on it that touches on the chromecast and apps to use https/www.techhive.com/article/249065/smart-tv/how-to-connect-your-iphone-to-your-hdtv.html
Look at the Vizio Smartcast. This option is at least free. But it... well it doesn't have the best ratings to be honest. But it might work for what you're trying to do. https/www.vizio.com/smartcast-how-to-cast
Also look at the Google Chromecast stick. It's not free, but it's less than an Apple TV. It won't let you mirror the phone to the tv but it should let you stream files local on your phone to the TV. This is a quick article on it that touches on the chromecast and apps to use https/www.techhive.com/article/249065/smart-tv/how-to-connect-your-iphone-to-your-hdtv.html