I’m not talking about meatfarming – that’s really not profitable at all in the game’s current state. What you do is find a farmable item that people are looking for. For example, tattered scraps of paper have been in high demand since the advent of Hobopolis, so going into the Haunted Library and olfacting bookbats would be a good idea. The economy fluctuates though, so there is no definite way to do it.

If you can’t stand farming, investments are the way to go. The monthly items *always* go up in price given enough time, and this can be used to your advantage.