With green screens, it can be as cheap or expensive as you like. If you want to just get a green background initially that costs hardly anything with standard room lighting, you can. Of course, the results won’t be amazing, but it's a starting point. If you want to broadcast using a green screen correctly, it can quickly become expensive. In addition to any fees for your software of choice, you also have to think about lighting, cameras, and having the space available. Green screens range from a few dollars all the way up to thousands of dollars for full kits. The best way to live stream with green screens is to start with something basic and scale upwards to something more expensive. This will allow you to become more familiar with the method without spending too much money at the start.