The short answer: Our prices depend on so many factors, it's impossible to say in one sentence. Avoid any web developer who can answer this question without a long talk.
The long answer: To get a better idea of the cost of what you want to build, give us a quick phone call. We'll ask you a few questions about the nature of the site, what sort of interactivity the site will have, your graphic design needs, etc. Then we'll be able to give you a ballpark figure. If you're still interested, we'll come to your place of business and come up with a firm quote.
If you talk to a web developer who gives you an instant quote, run away! Imagine telling someone you want a car and having them immediately giving you a price for that car. Any fair and honest car salesperson would want to know the make, model and engine type of the car you're looking to purchase, right? The same goes for building web sites. Depending on the features you want for your web site, the cost can be anywhere from a few thousand dollars to a few million.