So if the user chooses the first option they may need some knowledge of pd to actually run the patch. "put in a tad bit of work (learning) for the free version" which wouldn't be to hard to download and install pd then open a *.pd patch for somebody with no experience with pd.

Aside from the free download there will be a standalone exe compiled with the heavy compiler. I have no idea how to use it yet I have only read about it and if I understand correctly it is no longer being developed? but is available somewhere?. This version of the patch will only be available through donation of any denomination.

This will allow the user to use the patch without worrying about pd at all. For a small donation of $0.25 a dollar or whatever it may be.

Good Idea Or Bad Idea?

Would this be frowned upon seeing as pd is so open?

Is there any rules against monetizing a patch in this way?

Good Idea Or Bad Idea?

Hum... the pd community is small, I hope you don't need the money badly.

Would this be frowned upon seeing as pd is so open?

I like Reaper's model, free with a pop-up asking to pay eventually. I'm always willing to pay a beer to someone who share something that I use.

Is there any rules against monetizing a patch in this way?

I cannot say, but I think it will be fine.

However, if you use externals that are gpl licensed you might have to supply the source code or at least provide links to the source code I believe (though you can still sell the software despite it being open source, it just means people could compile it themselves if they wanted to)

Ardour has this kind of model https://ardour.org