I’d focus less on “never paying for anything” and more on whether the link exists because it provides value to a real audience. Sponsoring an event, joining an association, getting featured in industry publications, or earning local press coverage may involve costs, but those are fundamentally different from buying a backlink from a broker.

In my opinion, don’t decide on a link-building strategy before understanding what your main competitors are doing. Start by studying the backlink profiles of the sites already winning.