In reply to Nemanja Aleksic.

That would depend on what you mean. All plugins in the repository are free. No, we would not accept a do-nothing plugin that then requires you to buy the actual plugin from elsewhere.

But by "free" we mean as in speech, not necessarily free of cost. If a plugin exists to connect a site to a service which has no free tier, then that's acceptable.

For example, a video hosting service might require you to subscribe to it to host your videos there. Such a service has costs associated with it after all. Hosting and bandwidth aren't free. A plugin that connected that service to WordPress would be allowed even though the service itself is not free in cost. There's no requirement for them to provide a free tier.

Another example would be a site backup service. You pay for the service and storage, but the plugin that connects your site to that service and which even sends the backup data to it could be perfectly free and in the directory.