This is indeed a very good question. Many freelancers struggle with their quotation.
There are a few points that you have to take into considerations when you quote your amount.
I have listed these points below:
1. Number of dynamic pages and static pages.
2. Complexity of the website. (this includes twist and turns with page designs and icons used etc…)
3. If you are buying the domain for the client, then you certainly have to keep this point in your mind when you are doing your math while preparing the best possible quotation.
4. Costings may vary if you are using a CMS (Content Management System) or if you are hard coding the entire website.
5. Number of hours that you are going to invest on the website. (Designing, developing, testing and deploying)
6. Maintenance of the website.
7. And the most important part, your profit margin, this by far is the most important point.