Freelancing and web designing

Hello, this is the first time I'm doing this on my own (read: Unemployed and getting money by doing assorted works). The guys who want the page want something along the lines of this page:

http://hospital.apoka.com/hospital.html

Now, my question is, how much should I ask? It will be a rather lengthy job, but I do not want to rip them off. Any ideas?

i wish i was a freelancer,
i have always wanted a spaceship