I do not agree XF is expensive unless you want no branding (which for XF needs to be expensive to make sense), but I do agree that the emergence of paid plugins is a problem and I have stated this a few times before that this is not good for competition and customers. I prefer how it works on vb.org where you can hire coders privately and everything else is mostly free, or at least there is a lite version with the option of going full.
People are probably going to argue that with paid plugins in Resources you will see more releases but I would not agree with that argument. This has not been a problem with vB so there's no reason it would be a problem here. My suggestion is: require coders to provide a lite version if they choose to release a paid add-on. That is if you want to keep allowing paid add-ons at all, which seems to be the choice here. Personally, I would not have allowed paid add-ons to be released publicly. It's nice that the owners allow others to make money from their script, but they would probably benefit more from a completely free Resource section. Then create a sub-forum for paid requests.