I am exploring how to sell my new book

I am seeking a freelancer to assist with marketing and selling my non-fiction book. My target audience has already been established, and I am specifically interested in selling eBooks and hard copies. It is currently in English and I might go ahead and have it translated into more languages if there is an opportunity is there.

What marketing options can we opt for the most favorable result?
What are the channels you recommend we should cover?
What could be the budget for running these campaigns for 3-6 months?