Lucius T Fowler
Can be from nothing at all if you want to publish a personal weblog (with commercials in it) to anything like some hundred dollars a month, depending on how much traffic you cause. The modern internet is run by ancient phone companies, and the more traffic you cause, the more they'll charge you.
A usual fee for a private homepage should be no more than 5 or 10$ a month, but you need someone who does it or you, a person who will, depending on your demands, charge no less than 300$ for a simple page, or it can be easily more than 800$ for a webshop.
(That's what I charge. I put euros to USD 1:1)
Dave
That depends on a lot of factors. I recently commissioned a $57,000 website build. It totally depends on what you want the site to do.
Hosting can be as cheap as $5/month, or over $1000/month.
gogreen
Depends on the company you are dealing with!