Freelancer Question:

A formal bid letter is a great way to avoid any confusion over what's involved in the project. A phone call - which we'll talk about next - can help accomplish this also but there's too much risk for misunderstanding when it's not in writing.

And as the one hiring it's your job to communicate exactly what you need done. If you need someone to write all the copy for your site don't just say, "How much would you charge to write the copy for my website?"
A better way to ask this would be, "I need copy written for the following pages: Home, About, Services, Our Team. I need headlines on each page and will also need meta-descriptions written for each page using our keywords of Muscle Cars for Sale."

Be specific. And get it in writing.