This is a great idea and I’m all for anything that can be done to support developers.
I did want to mention, though, that in my experience recognition and appreciation are a lot more important than money when it comes to developers.
Most MODx users would be absolutely stunned at the amount of time it takes to create, support, and maintain a MODx add-on component like FormIt, Login, TinyMCE, CodeMirror, or getResources. Most people can sort of imagine the hours of code writing it might take (though they’re probably off by at least a factor of 10), but they forget about testing, improving, redesigning, tweaking, starting over from scratch, writing documentation and comments, creating and editing lexicon files for all messages and properties, updating for new versions of MODx, creating the build script, uploading the package to the repository, entering the information in the repo forms, etc. etc.
They also don’t realize that every non-trivial change to the add-on usually means updating the changelog, readme.txt, comments, online docs and tutorials, version number in multiple files, GitHub readme, build script, lexicon files, and repository info, etc. No one in his or her right mind is going to take that on for $200 or even $500, and someone doing it for the money alone isn’t going to be around very long.
Too often (and I’ve been guilty of this too), a new package comes out and two or three people say "Thanks, this is great," while dozens more say either, "Something’s wrong with this package, I can’t get it to work," or "This package is useless to me because it won’t do X."
I just wanted to take this opportunity to say a huge *THANK YOU* to all the developers whose hard work went into MODx itself and all the add-on components I use every day in MODX. We can’t say it enough.