Home Solar Power Guide Where I can get solar power kit for my house?

Where I can get solar power kit for my house?

I am looking for a solar power kit for my house but I don’t h know what should I look for before buying solar power kit and how much energy it generate. And I’ve been hearing that it can cost an excess of $20,000 for a whole professionally installed system. Please suggest me that how much watt solar kit need for my home and should I purchase a new one or used solar power kit as new one is really expensive. Please suggest.