WDD.org.uk lists a range of web design companies all offering similar services and a range of web design prices. For a customer there are several burning questions before making your choice and price seems to be at the top of the agenda. Prices quoted will differ wildly from company to company. Some quotations are nothing more than web design agencies licking their index figure before raising it in the air others will attempt to charge you the price they think you are prepared to pay, the best outfits will break down the costing and explain in everyday english what you are being charged for.
It's important to note the most expensive companies will not necessarily offer the best service, they like all businesses having overheads and employees to pay, its quite possible you could get the same level of service from a one man band who intends to produce the various parts of the website themselves (design,development,seo) .
Choosing a single person to produce all the sites runs its own risks, therefore having a team people behind the project is generally desirable.