Denny's parents want to be cord cutters, get their TV from the internet, and use their wireless data. Leo says they'll need at least 10 Megabits/second download speed to watch Netflix in HD. He can check at fast.com to see how fast their internet connection is. Going beyond the data cap will cost them money, and that can happen pretty quickly at .5 GB an hour. Cable companies charge more for internet if they choose not to buy a whole TV package. Leo also recommends getting the over-the-top TV service like YouTube TV for $40 a month. But at the end of the day, they're probably going to spend almost as much as that monthly cable subscription.
Another option is to get a TV antenna if they live in an area that has direct access to transmitters. Check out TVFool.com