Many communities begin as small projects and hobbies. They start as a passion and the creators pour their time and money into the project. As a community grows, though, the need for new hosting, different hardware, new servers, or other things that cost money grows. This hobby is now suckling on the creator's wallet.
There are methods to relieve this financial burden though. Ads can be displayed, donations/contributions can be solicited, or "cover charges" can be applied. All of this introduces friction in the community though, because a once free product now has a financial component to it.
How can I, as a community leader, introduce these monetizing options without enraging the community? To be clear, I am not asking what my options are to monetize the site. What is the best way to explain to the community why I need to monetize the site?