Site pricing help

started workin on a site a week ago…and heres my hours so far:

5 sessions of 4hours =20 hours

i’d say i’ve done 50-75% of the site

Its css+xhtml with some little flash things, so i’d say £400 ($705) is the minimum i should charge for what i’ve done so far. Would you guys agree?

P.s. if someone could suggest a ballpark figure on the info above then that’d be great. I dont really want to give any more details about the site.