The cost of On-Page SEO can vary a lot depending on who’s doing it and how big your website is. If you hire a professional agency or SEO expert, it can cost in between 300- 1,500 USD or more per month. For small websites, it might be cheaper. You can also try doing it yourself using free tools, but it takes time and effort to learn. It’s like fixing up your home—you can DIY or call in a pro.