I´ve to make an offer to a client who wants me to develope a web-service for him. I have some trouble calculating the pricing - can you help me?

Here is a rough outline of the project:

It´s a portal on which various artists and entertainers can register and administrate there profile (texts, gallerie, some embedded videos, choose categories and radius of offer, etc).

Other user can browse the artists by 3-4 level categories and countries/staats.

If someone wants to hire a artists, he can put them in an "shopping-basket" and can mail everyone in his basket. The Artists can answer them with a form on the website (he doesn't get the email of the other person).

Users should be able to comment/rate the artists. But if an artists wants this comments/ratings visible on his profile he must pay, and after that, the admin of the site must activate this comments/ratings.

So, no more information given, what would you charge (ca.)?

Edit: It´ll be developed with php/codeigniter. A .psd design is already there.