Here are several articles on the costs of having a web site.
Your total costs involve up front fees for web design or software, plus ongoing costs for your domain, hosting, SSL, and marketing.
Do not forget to include your soft costs such as staff time spent creating the site and responding to visitor requests.
The key to managing your costs is knowing what items are necesssary and which items are being product dumped on you. Keep in mind that a web site is not an asset, it is not an investment, it is an expense that should be managed like any other.
Some of these pages discuss our pricing specifically, but they are sprinkled with general information as well.