If you are having a new website created then you may have to decide if you want something that is totally bespoke or if you are happy to have a site that is based on a theme. Many web building software packages such as WordPress, allow you to install themes which can then be amended to suit your business. Some web developers create their own theme, others will use a theme that is either free or they have bought and adapt it.
When costing up a website, it is important to know what you are being offered. If you are being sold a bespoke website then it may still be based on a theme but certain elements will be bespoke to your business. You do not need to necessarily have a fully bespoke site.
If a theme is being used then you may want to find out how other many sites are using the same theme and how much it can be adapted. All good programmers will be able to adapt a theme to suit your business and even if they have used it for other customers, amend it enough that it still looks quite unique. Often just changing the images, colour ways and menus is enough to make a site look quite different from another built using the same theme.