Well that would not be hobby expenses, but necessities. You also forgot scotch and Cuban cigars. Trey
My original answer was 100 bucks . But after thinking about it more , I'd have to say I spend more like 2 - 3 hundred bucks a month lately . With the M1's and adding sound to other steamers , it adds up quickly !
I now have most of what I need. Though, truth be told, like many others, I waste close too, $100 a month on useless...(not model train)...not needed stuff.