
Prices for websites can vary wildly.
Here's a rough guide - as relevant to a corporate client as it is to a small business:
£500 - £1,500 will buy you a templated website from a low-budget agency. The site may look ok, but it will be an adaption of something they've already sold. The technology will be dubious - probably not very search engine friendly and difficult to manage. You might get a few standard features, but any bespoke work will cost as much as if you went with a professional agency.
£2,000 - £15,000 should be enough for a properly built website for most small to mid-size businesses. You should expect a range of features and a high standard of design. Choosing the right agency is the biggest challenge - some will be better on technology, some on design.
£15,000 - £25,000 buys a fairly sophisticated website for the smaller corporate customer - either because a lot of work has gone into the design, it has a lot of pages (100+) or because it has several bespoke features.
£25,000 - £50,000 sounds like you are being charged too much - unless you are a mid-range corporate client that needs a range of features - say 200+ pages of content, multiple languages, integration with back office systems and lots of account management to ensure everything runs smoothly.