Hi there. I see that you need cost evaluation for a website, and living in this day and age, that evaluation can vary on many degrees. I will make few assumptions, for example, to get the cost of a front page, for example, I will search the similar projects with the similar design here on freelancer, upwork, Dribbble website, and extract the prices to get the realistic and concrete price for the work done.
Similarly, I will check to see the price for development of that front page, the average price for that work done.
As you can see, these will be safe assumptions based on what already happened, so not much theoretical stuff around here.
Anyway, feel free to hit me up so we can talk more about this. I am very responsive. All the best