Ask HN: As a skilled developer, how do you make pocket money with little time?

Hi, I'm a web developer and I search a way to get extra money, in a regular way if possible.

I tried to be a freelance, it is well paid but with my full-time job it's too time consuming and I'm not so ambitious.

I'm not here to make advertisement but to hear your experience. I'm considering security audit, consulting and things like that be it's the same as to be freelance: you need to search for prospects, etc.

Do you have some clue or experience?