Fast answer
Use free SEO tools while validating the niche. Consider Semrush when publishing consistently and making decisions based on keyword gaps, competitor pages, and rank tracking.
Free stack
- Google Search Console
- Bing Webmaster Tools
- Manual search result review
- Simple spreadsheet keyword map
Upgrade when
- There are 20+ useful pages live.
- You need competitor/topic gap research.
- You can act on the data weekly.