There are several affordable marketing and promotional services available for self-published authors. One option is to use social media platforms to promote your book. Create social media profiles and engage with your audience by posting interesting content related to your book. You can also run targeted Facebook ads to reach a larger audience. Another option is to use book review sites such as Goodreads, Bookbub, and NetGalley to reach potential readers. You can also join writing communities and forums to connect with other authors and readers. Lastly, consider hiring a book marketing agency or consultant that specializes in promoting books. A simple Google search for "USA best authors near me" can help you find the right agency or consultant that can help you promote your book within your budget.