Copywriters charge according to their expertise. Some copywriters charge by the hour; others charge by the project.
I charge by the project, which is fair to the client: the business that's hiring my services knows exactly what the cost will be.
Email me and send me a brief, and I'll be happy to quote on it.
The brief is a set of instructions, a task description. It's your plan of exactly what you want the writing to do. If you're not sure what it is you need, tell me your challenge, and we'll discuss it.