If you do something well, never do it for free. That may be something you heard from your father or grandmother at some point during your childhood or adolescence, but it doesn’t really set in until you truly get out into the workforce. In other words, whether you’re an SEO working at a large firm or a small company, you’re not going to do projects just out of the goodness of your heart. You’re going to want to make some money. But the problem is…how exactly do you charge for SEO services? I have found this site https://www.buscado.com.br/agencia-seo.html but does note help me so much.
By month and allocation of tasks. If you charge by keyword ranking, you won't have a guarantee that you will make money, as it is easy for SEO to fluctuate based on the conditions of the time and updates that happen as well as the dynamics of the website.
If you charge by month, identify which tasks that you have completed and offer to add in audits to showcase how the keyword rankings are changing. SEO is more than content, so add in different types of services within SEO, such as internal / external linking and how much, optimisation of content, technical services for the website. Define how much you want to charge with each of these.
I've worked with SEO clients for over 12 years and can help you too build your business as well!