Need information about starting a charity computer support business?

I want to help financially struggling small businesses and low income people with their computer needs by offering free service. My purpose is not do this free all my life of course, couldn't do it for too long. I want to be able to make money off of it at some point since it will take my whole day doing this and I will have no other source of income. I want to know how I can do something like this and at the same time being able to survive financially.