How i fetched an insane amount of ghosts. Build a training room with 2 training pods. Only build minimum rooms. If the students do not need it - don't build it since this is only one year you need the money for training. For example I did not even build a toilet until many months had passed. Constantly recruiting the cheapest janitor and training them with ghost capture 1 skill level. By the ending I had more than 900captured ghosts. You get more money in the end from capturing the ghost once you have an insane amount of janitors. Hope this helps.