Hi @JustJohnySk ,
I disagree with @RecourseDesign , I don’t believe is realistic to earn 500 euros a month, no matter how talented or how many hours you put in. The reason is the 1 time payment system (purchase and own forever). You may get to 500 euros in one or two months but Game studios are very limited and they’ll eventually own all your work.
So unless your producing plugins and game systems like they do candy in India (1000 per second) 
… your up for big disappointment. I would see this as a freelance side or hobbie job, not a full time job. At least not until they incorporate a recurring income for us. 