Wow! $89! I say start at $30. I've been looking into doing some freelance proofreading and translating, and I've seen wages here range from $20-50. Make sure you bring up your writing, proofreading, and English language skills and how important accuracy in writing is for effective communication. Focus on how good writing reflects a business' dedication to quality and organization.
I don't know much about Donald Trump, but he has written a number of books. Could you check some out at your library and skim through them? Get some ideas?