The cost of web development services can vary widely depending on the nature of the project, its complexity, the expertise of the developers, and where they're based (an offshore company would usually offer high-quality services at a lower price).
On average, smaller and simpler projects can cost a few thousand, while larger and more complex websites can cost tens or even hundreds of thousands of dollars. To understand the exact cost, it's best to get a detailed quote from your service provider before you start the project.