Amphibian.com

I hate most "free" apps for this reason. I don't want to see ads all the time or be tracked and have all my data sent to some server in China. I'd be happy to pay a few dollars for a good app, but now (on iOS at least) too many have switched to a subscription model. I really really really don't want to subscribe to an app for $5 per year. I remember in the old days when you could just buy software once and run it for as long as you wanted to.

Also, you may be interested in this explanation of the different types of free software.