If you are only wanting to live stream your service, you could get it done with only a cell phone and a tripod. However some services like to include their own B-roll Videos, using multiple cameras and microphones for different takes. Which then would require a type of video switcher along with some decent cameras and that is when things could get costly.
If you are wanting to stream to multiple social media sites at once such as Youtube and Facebook I recommend using a service called Restream.io, which can be used with a cell phone or a Workststion / Laptop with a camera and a Mic connected. Recommendations for Streaming software, Camera, Mic input for XLR microphones.
Please let us know more about what kind of live stream you want to offer and we can help tailor a solution.