Libraries, public goods, gifts, open-source work, advertising, and venture subsidy can all produce experiences free at the point of use for very different reasons. Treating them as one model hides who funds the benefit and what obligation travels with it.
A useful evaluation asks who pays, what is collected, and what happens when funding changes. A visible €0.99 can be easier to reason about than a zero whose business model arrives elsewhere.
Zero answers the amount, not the arrangement.Read the privacy posture