How much would you charge for on-going SEO?

For example, how much would you charge per month for a keyword with 2000 monthly searches(exact match) with low to medium competition?

The payments would begin when the website is in the top 10 websites for the keyword.

Additionally, how much would you charge for advice on on-page SEO?
Please also share strategies for gaining brick and mortar business for SEO contracts!

Thanks!


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Seo|Seo UK