if you finish the second dungeon you can go back to the subway where you will find a notice for a job at an office and can make money there. you make more money there than the restaurant.
You have to finish dungeon 2 first then go back to the subway where you interact with a notice on the wall which starts a side quest that will lead you to the office
i guess wait for a week then go back to the subway, there is a paper on the wall that you have to interact with over there, if it doesn't work then it might be a glitch and you have to talk to the creator then
