The three things that actually determine cost
Design complexity is the first lever. A site built on a proven template with light customization costs far less than a fully custom design with bespoke animation, because the design work itself - not the code - is often the bigger time investment for a premium build.
Feature scope is the second. A five-page marketing site is a different project entirely from an e-commerce store with payment integration, or a platform with user logins and a database. Every added integration - payments, booking systems, CRM connections - adds real development and testing time.
Who you hire is the third. Freelancers are typically the most affordable for a single, well-scoped project. Boutique studios cost more but bring a full team and continuity. Larger agencies cost the most, partly because of process and account management overhead that comes with bigger engagements.
What's usually included versus billed separately
Design and development are almost always included in a quoted project price. What often isn't: ongoing hosting, domain costs, premium plugins or licenses, stock photography or custom illustration, and post-launch changes beyond an agreed revision window. Always ask what happens if you want a change three months after launch - some studios include a maintenance window, most don't by default.
How to get an accurate quote instead of a guess
Come to the conversation with a clear list of pages, must-have features, and 2-3 reference sites you like the look and feel of. Vague briefs get vague, inflated quotes because the studio has to price in uncertainty. A specific brief gets a specific, defendable number.