Search the internet and you'll find thousands of web design companies looking for your business. It's a bit like commissioning an architect to design a building; you need to pick the right web designer to design and build your site.
For a really simple website expect to pay around £500. Certainly, there are ways to make a cheaper website, but to be honest, it's often a more efficient use of time and money to commission a web company to oversee the process for you.
Most businesses don't need a feature rich website, they just need a professional looking web presence that conveys simply information about what you do, and how people can contact you. Think of it like an online business card.
Most companies will provide a quote for building your website. The more information you can provide them with, the easier they'll find it to produce an accurate and hopefully competitive quote. Think about exactly what you need when you request a quote. Here are a few ideas that you may want to consider.