If you want to hire someone to help you SEO, the price can range from $75-150 per hour for an SEO expert ($750-$1,500 per month). High-end digital marketing agencies may charge up to $20,000 per month for complex jobs for large websites. Additionally, SEO tools are either free or cost around $99 per month. The first step to knowing what to spend on SEO is to calculate your return on investment (ROI) based on your website and niche.