The honest answer is scope
A simple landing page, a multi-page business site, and a custom web app are very different projects. Cost depends on how much strategy, writing, design, development, testing, and post-launch support the site needs.
What usually drives the price
The biggest cost drivers are content complexity, number of unique page layouts, forms, integrations, custom visuals, SEO setup, performance work, and whether the site needs ongoing updates.
A better first question
Instead of asking only what a website costs, ask what the site needs to accomplish. A site built to generate qualified inquiries has a different structure than a simple online brochure.