As everyone has said, and I simply skimmed the replies, you need to have a better understanding of what they need.

Do they need custom scripts?
Do they need a Content management system(cms)?
Are they having you update it monthly?
ETC

There will be a cost to develop and design the website, as-well-as a cost for monthly retainer to have work done. Make sure this contract gets viewed over by a lawyer as what you described will be an expensive job.