[jggube]

When you say "website", is it content-driven or a web application/tool? Either way, ads would be a good (only?) option.

If it's content-driven, you can do premium content stuff (like eBooks, downloadables, etc.)

And when you say "enough money," how much are we talking about? It's all relative: the more traffic you get, the more money you get. I would focus on growing your community and audience before even thinking about monetization. Have that behind your head, of course, but you're not going to make money if you don't have traffic or a community. You're not going to make anything significant if your product sucks. Focus on the product first, the money will come eventually. It's an investment of time and a bit of money (web hosting on a VPS is like $20 a month and you just scale when you need to).