depends what you are making it with... flash usually costs more.
the price depends on the person/company.
you need to think about this: (as these should be included in the cost)
1. Domain Name Set Up (30/60/100 bucks depending on where you get the domain for - overseas domains are cheaper (.com) than australian domains (.com.au).but Australian companies will often want .com.au names.
2. Hosting: generally - hosting IN australia is expensive... but its probably better for an australian site to get it in australia. you need to make about a $300 allowance for hosting setup and a few months/year of hosting.
Offshore is usually cheap as - like - you can get a year's hosting for less than 50 bucks - but i don't know how reliable it is...
You should look for: cgi/php/perl, log files which you can access, stats, mail, uptime.
3. Profit: obviously you want to make a profit after you pay for these things.
Check out
http://www.webdesigners.net.au
theres heaps of stuff there.