Among the cheap methods that you can use for the first time to promote your book are advertising networks, which provide good advertising services on a large scale.
One of the advertising networks that I can suggest to you that can help you promote on a large scale is ELeavers (You can find it by searching in the Google engine) and you can customize your advertisement through it with ease and target any country or region.
In return for dealing with it, you can get a good result and notice an increase in traffic for your business and many other benefits are available.
You can also monitor the performance of your advertising campaigns via the dashboard, and from there you can know all the details about your ads.
In addition, there is a support team that you can contact if you need help or have any questions about anything.