Ask five providers for a website and you will get five quotes that differ by a factor of twenty. That is not because four of them are cheating you. It is because "a website" describes wildly different things, and the quotes are rarely for the same one.
Here is what actually moves the number, so you can compare quotes on something real.
The cheapest tier: a theme with your content in it
At the bottom of the market you are buying a purchased template with your logo and text substituted in. It can look perfectly decent on launch day. What you are not getting is anything built for your business specifically, and typically no technical SEO, no performance work, and no testing beyond "it opened".
This is not automatically the wrong choice. If you need a presence so that people who already know your name can find your phone number, it may be all you need. It becomes the wrong choice the moment you expect the site to generate enquiries.
The middle: custom design, standard functionality
Here you are paying for design and build specific to your business, mobile testing across real breakpoints, working forms, image optimisation, proper heading structure and schema, and analytics configured rather than merely installed.
Most small and medium businesses that want the site to actually do something sit in this band. The cost is driven mainly by page count and how much of the content you supply versus how much has to be written for you.
The top: applications, not brochures
Once you need users to log in, data to be stored, payments to be taken, or your site to talk to other software, you have left website territory and entered software development. Price scales with the number of distinct things the system has to do, and it should be quoted per milestone rather than as one lump.
The costs that are not in the quote
These catch people out more than the build price does. Domain renewal every year. Hosting, monthly or annual. An SSL certificate, often bundled but not always. Paid plugins or licences with their own renewals. Stock photography. Email hosting for addresses on your domain. And maintenance, which is either a retainer or an unpredictable per-fix cost.
Ask for the total first-year cost including all of these, not the build price alone. A cheaper build with expensive locked-in hosting is not cheaper.
What actually drives price up, legitimately
Number of unique page layouts, not number of pages — twenty pages using three layouts costs far less than six pages each designed separately. Whether content and photography are provided or created. Integrations with other systems. How many revision rounds are included. And whether SEO and performance work are in scope or sold separately later.
Four questions to ask before paying anyone
First: will the contact form be tested and will you show me an enquiry arriving? Second: who owns the code, the domain and the hosting when this is finished, and is that in writing? Third: what exactly is included in the price and what will be billed later? Fourth: what happens after launch — how long is support included, and what does it cost after that?
A provider who answers all four clearly and in writing is worth more than one who is twenty percent cheaper and vague. The expensive mistake is almost never the build price — it is paying twice because the first site could not be fixed or handed over.