There is no way getting around at least a one off payment $19 for someone to develop content for your game with out you developing your own tools. While you may loose out because there is a lack of community made content for your game (shouldn’t really be building your business model around that anyway in most cases), I think most moders really want to make there own game anyway (if not they would be better off choosing a AAA game to mod for generally) and this way Epic also benefits as they are more likely to continue their UE4 subscription.
If you really want an editor for free base your game off the lastest udk and your customers can download the exact same tools you used with out you having to do any work yourself.
Bottom line if you need community content for your game to work, then developing your own tools would seem to be an important use of your “precious time”.