Book marketing and book promotion are not the same thing.
Book marketing is letting people know that you, the author, and your books exist, and clearly conveying what they're about.
Then giving people an easy way to purchase them when they find them.
Book marketing is ongoing. As an indie author, you add to it and tweak it all the time. It includes everything from your website and social media presence to your bookmarks and business cards.
The creative way to approach book marketing is to see it as another way to convey the passion and mission that are embedded in your book.
Book promotion kicks in around a particular book. It's a push that has a start and end date.
When people talk about hiring somebody to “do their marketing”, they often really mean promotion.
Nobody can do your marketing except you. You can get some guidance but creative book marketing is really about capturing the heart and soul of your book(s) in smaller writing segments: tweets and other social updates, postcards, trailers.
Promotion, like Amazon ads or services like Bookbub, are often mechanical and can be outsourced but you should never hire a book-marketer from a position of ignorance.
Before paying for any aspect of marketing, have three things in place:
1. Know what kind of author you are and where you and your books fit in the books ecosystem.
Where are you found in a bookstore? What are your categories, subcategories, keywords?
2. Understand what sort of promotion works for this specific book, readers and micro-niche
Are you reader actually all that price sensitive? What other kind of promo might work for a book like this? What would be super-cool, and not too costly, that you'd love to do?
3. Explore the channel yourself first and know how it works.
Don't invest in something you don't understand.
Money can buy some sales, through ads, publicists, effective trailers and websites, good advice and so on. But if you’re not working within the proper context, of genre and category, and from a position of knowledge, you are likely to waste money to little effect.