I use Portmaster (on Linux) and I have never seen ads (either in the app or apps that get their DNS from Portmaster) on it. About the only thing I saw different between the free version and the base level paid for version was traffic history and weekly reports (and badges on Discord if that's your kind of thing).
Both used to be free. And you may not consider it advertising when unavailable features exist in the free UI just to tell you they're paid, but I do. Especially when they used to be free.