The business of...religion?

Probably a touchy subject, but something I've always been curious about. For those independent temples/churches, how does one go about setting it up and 'making money' from it?

We've all heard stories of temple head honchos or church pastors making big bucks (but small offices also exist)

How are they audited and how do they split the money received between paying themselves, the staff and savings for their building/maintenance? Can someone just straight up start a temple/church?

Are there any temples or churches that closed due to lack of funding?