This is kind of a backwards question because it depends HEAVILY on your experience. Living within the United States, I constantly do freelance work on the side of my main job. In order to create a fully custom Wordpress Site (including installation of design and wordpress on the server), setup social network accounts, light SEO and basic training) I would say if you only have a few years experience than charge around $600 - $700. However, if you have more experience you can easily get $1,000 + from the client once you explain how important SEO is (which can make up a bulk of your price), label it as " Online Marketing "
My professional experience in this comes from working as a software engineer at a design agency for the past 4 years.. it was a very rewarding experience.. If you have any other questions, just let me know.