The reality is an HTML website is simple to put together. Considering there are many options out there for the do it yourself-er if you are extremely budget minded you may approach you new site from that prospective.
Companies trying to sell you a many thousand-dollar site will not tell you that driving folks to that site is not really done on the front end. Now let’s be clear you do need a functional site. A site that creates an experience that makes people want to stay or buy, whatever your need may be. HOWEVER driving people to the site is all done through SEO, and you do not need these experts for that either.
For the budget minded go to YouTube and follow guys like Neil Patel. He is very smart and shares tips and tricks that he uses for FREE. He is giving this information away because it is how he finds clients that can afford to pay for his service. Neil is not a fake or a fraud he is the real deal giving you the real scoop for free.
If you have some paper to spend on driving traffic use Google pay adds, and you will get traffic guaranteed. It is not cheap depending on your preference of keywords, but it works. Think about saving money on a site upfront and using that money to buy adds and kick-start your traffic.
So, with that said what should you pay for a site on a freelancer type site? For 12 to 20 pages of HTML in WordPress I would not pay more than $1000. I would aim for $500, but it may be worth it to put out a touch more and push for exactly what you want.