Good SEO Tool for small size business

I was used to work with Tools like Sistrix, Ahrefs or Searchmetrics and did not know about SE Ranking before. But those tools were too cost-intensive for a small and quick start into SEO so I tried it out and I am quite satisfied with it. I like the ability to pay for certain services with credits, as I am not using them on a very frequent level, so it actually gives me greater flexibility to only use them when needed and not paying for them even when not using them.