Getting the /blog off my domain

I have a unique situation. I DO NOT need instructions on how to go from 6789.com/blog to 6789.com. What I’m looking for is the going rate or a fair price that I could expect to pay to have someone do this for me.

I hired someone to look into this and quote me a price. They went in and rather than looking at something, did something the made my entire site dissappear and said it was just a coincicence, he didn’t touch anything and that WordPress is unstable. Then told me he could fix the site and get it back for $150. Which I didn’t agree to and he did anyway. I have no problems paying the person for fixing my initial request even though he didn’t quote me, he screwed it up. But I do have a problem paying for the guy to fix the site that was never broken until he screwed it up.

So if I were to simply hire someone to change the files so that my domain is 6789.com instead of 6789.com/blog. What could I expect to pay someone for doing this for me?