SEO tool recommendation for Small and Medium enterprises at affordable price

There are plenty of tools to choose from, free and paid. All with various options and the corresponding prices. I once made a small overview of both free and paid SEO tools. Maybe there's something in there for you.

Thanks for info

Recently I heard about the app NinjaSEO by 500apps. do you have any idea, how effective it is?

Wel with fewer than 10 installations on Wordpress it isn't the most populair option. Don't know the quality.

Thank you so much