I think no one replied because it'd take a week to explain everything - LOL - but I'll take a stab at the specific questions you asked
Money:
You need a domain & hosting, which at 1st will be minimal costs. Depending on what things you can & can't do yourself, you'll need to have the site designed. If it's a paysite you'll need to have an account with a credit card processor & have that set up on your server. If you're going to host the cam yourself, you'd need to have all that programming set up too.
If your going to buy traffic or pay webmasters per sign up, you'll need some cash for that as well.
Legalities:
That's a tough one - I'd get a lawyer & ask him to do some research ont he laws & whatnot, as I am not one & any advice I gave would be just that - advice