Quick question on paid mods

Pardon my ignorance on this question. But I'd love a bit more info on this. I tend to be sceptical on games that add systems that promote micro transactions. As paid mods for this game go, they appear to be of a good quality and I don't dispute paying mod creators for their hard work. However, I'd like to know where my money goes.

If for example, I buy a mod for 500 credits, how much of that actually goes towards the author? Moreover, for you mod authors out there, do you feel that you receive a fair share of this?