That depends entirely on your individual needs.
Some design companies give straightforward 'package' quotes.
We do not. Every client has individual requirements, and as such each site we design is as unique as the client for whom it was created. The actual design of your site is only one consideration. There are other things that you will need to budget for, regardless of who you choose to create your site. Thought should also be given to items such as web site hosting, a domain name, promotion and so on.