How to find keywords without paying for a tool
Every keyword tool wants $99 a month before you have a single visitor, and you are not sure you would trust the volume numbers anyway.
Write down the words, theirs not yours
Not your category name. The literal string a person types when they have the problem. People do not search for document workflow optimisation, they search merge pdf online free. If you cannot write twenty of these without inventing any, that is your answer about the product, not about the research.
Confirm humans type them
Autocomplete only suggests what people have actually searched. People Also Ask shows the questions attached to a topic. Forum threads and support inboxes show the phrasing. Anything that survives all three is real, and no subscription confirmed it.
Judge the weakest result on page one
Volume tells you the size of the prize, not your odds. Look at the weakest page currently ranking. If it is thin, generic, slow or ten years old, the query is takeable. If every result is excellent and well-resourced, the number next to it does not matter.
Search Console is the keyword tool you already own
The Queries report is a list of things real people typed and saw you for, with your actual position on each. No paid tool has that, because no paid tool knows your site. Sort by impressions, filter to positions 5 to 20, and you are looking at demand you already touch and are not yet collecting. That list is worth more than any volume estimate.
The queries you are not ranking for yet
For those, read results pages rather than tools. Search the thing your customer would search, then read what Google auto-suggests, what the People Also Ask box contains, and what the related searches at the bottom say. Those are Google telling you, for free, what it believes the adjacent demand is. It is the same data the tools resell you, one step earlier.
Measured, not asserted
The largest query in this site's category returned 45 clicks in seven months, then fell to 5 clicks at position 35.76. Two obscure phrases nobody would target on purpose returned thousands. Sorting the list by volume would have produced exactly the wrong plan.
Free tool for this: SERP Preview. No account, nothing uploaded.
Where this goes deeper
Every number on this page comes from one complete dataset: one product taken from zero to 100K+ users on search alone, with nothing spent on advertising. The full argument is Chapter 1 and Chapter 4 of the book. Five chapters are free to read.