Literary agents typically involves a percentage of the author's earnings from book sales. This commission is usually paid once the book is sold to a publisher. The standard commission rate is typically 15% of the author's net earnings from book sales. However, it's important to negotiate and understand the terms of your agency agreement. Some agents may charge additional fees for specific services, such as marketing or legal representation. If you're exploring self-publishing options, consider the range of services offered by Book Publishing Services and their associated costs. Ultimately, the decision of whether to work with an agent and the terms of your agreement should be based on your individual needs and goals.