The cost of a responsive website design agency depends on the project size, complexity, and required features. A simple responsive website with basic pages and standard design may cost between $500 and $2,000. For a more professional responsive website design agency project with custom UI/UX, mobile optimization, and CMS integration, the price usually ranges from $2,000 to $5,000. High-end websites with advanced animations, eCommerce features, and custom development can cost $5,000 to $15,000 or more. The agency’s experience, location, and reputation also play a big role in pricing. Additionally, ongoing maintenance, updates, and hosting may add extra monthly costs. Overall, the final price depends on the scope and quality level of the website you want.