Quite a lot of tools are actually really just free. Say, the Linux kernel, or most of the free software we all use everyday.
Then there are also the miscellaneous services run by someone on the internet mostly for themselves or a small community (or just to get some publicity for themselves) which are also free and don't run on ads, selling data or subscription. I do that, myself. Do you trust Naptha[0]? It was posted on HN some time ago, from the comments[1] I don't even see anyone bringing up the issue of trust.